JP4303333B2 - Film for optical elements - Google Patents

Description

【００３５】
構造式１において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ¹⁰は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₂ 、Ｘ₃ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ およびＸ₃ の有機基において、結合手が左右逆となる構造式も包含する。
【００３６】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００３７】
【化２】

【００３８】
構造式２において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ¹⁴は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₃ 、Ｘ₄ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ 、Ｘ₃ およびＸ₄ の有機基において、結合手が左右逆となる構造式も包含する。
【００３９】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００４０】
【化３】

【００４１】
構造式３において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ¹⁸は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₃ 、Ｘ₄ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ 、Ｘ₃ およびＸ₄ の有機基において、結合手が左右逆となる構造式も包含する。
【００４２】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００４３】
【化４】

【００４４】
構造式４において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ¹⁴は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₃ 、Ｘ₄ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ 、Ｘ₃ およびＸ₄ の有機基において、結合手が左右逆となる構造式も包含する。
【００４５】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００４６】
【化５】

【００４７】
構造式５において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ¹⁴は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₃ 、Ｘ₄ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ 、Ｘ₃ およびＸ₄ の有機基において、結合手が左右逆となる構造式も包含する。
【００４８】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００４９】
【化６】

【００５０】
構造式６において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ¹⁸は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₃ 、Ｘ₄ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ 、Ｘ₃ およびＸ₄ の有機基において、結合手が左右逆となる構造式も包含する。
【００５１】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００５２】
【化７】

【００５３】
構造式７において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ¹⁸は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ 、Ｘ₃ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₄ 、Ｘ₅ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ 、Ｘ₃ 、Ｘ₄ およびＸ₅ の有機基において、結合手が左右逆となる構造式も包含する。
【００５４】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００５５】
【化８】

【００５６】
構造式８において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ²²は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ 、Ｘ₃ 、Ｘ₄ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₅ 、Ｘ₆ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ 、Ｘ₃ 、Ｘ₄ 、Ｘ₅ およびＸ₆ の有機基において、結合手が左右逆となる構造式も包含する。
【００５７】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００５８】
【化９】

【００５９】
構造式９において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ⁶ は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ およびＸ₂ の有機基において、結合手が左右逆となる構造式も包含する。
【００６０】
【化１０】

【００６１】
構造式１０において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ⁶ は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ およびＸ₂ の有機基において、結合手が左右逆となる構造式も包含する。
【００６２】
【化１１】

【００６３】
構造式１１において、Ｒ¹ 、Ｒ² は炭素数１〜２０の炭化水素基、Ｒ³ 〜Ｒ¹⁰は水素原子、Ｆ、Ｃｌ、Ｂｒ、炭素数１〜６の炭化水素基あるいはアルコキシ基、Ｘ₁ 、Ｘ₂ は単結合あるいはＡ群から選ばれる少なくとも１種の有機基であり、Ｘ₃ 、Ｘ₄ は単結合、−Ｏ−、−Ｏ−（Ｃ＝Ｏ）−から選ばれる有機基である。但しＸ₁ 、Ｘ₂ 、Ｘ₃ およびＸ₄ の有機基において、結合手が左右逆となる構造式も包含する。
【００６４】
Ａ群
−Ｏ−，−（Ｃ＝Ｏ）−，−Ｏ−（Ｃ＝Ｏ）−，−ＮＲ₁ −（Ｃ＝Ｏ）−，
−ＣＲ₁ ＝ＣＲ₁ −，−ＮＲ₁ −（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−Ｏ−（Ｃ＝Ｏ）−ＣＲ₁ ＝ＣＲ₁ −，
−（ＣＲ₂ ）_n −（ｎ＝１〜４），
−Ｏ−（ＣＲ₂ ）_n −Ｏ−（ｎ＝１〜４），
−（ＣＲ₂ ）_n −Ｏ−ＣＨ₂ −（ｎ＝１，２），
−Ｏ−（ＣＲ₂ ）_n −（ｎ＝１〜３），
−Ｏ−（Ｃ＝Ｏ）−（ＣＲ₂ ）_n −（ｎ＝１〜２），
−（ＣＲ₂ ）_n −Ｏ−（Ｃ＝Ｏ）−（ｎ＝１〜２）、
（Ａ群中、Ｒ₁ およびＲ₂ は水素原子または炭素数１〜１０の炭化水素基を表す。またＲ₁ は、互いに同一である必要はなく、さらにＲ₂ がｎ個ある場合には、それぞれ異なるものであってもよい。）
【００６５】
以上のような構造を有する当該化合物の合成方法については特に制限はなく、当該分野において公知のいかなる方法も採用可能である。また当該化合物は、純水な化合物である必要はなく、配向性を落とす、着色するなど本発明のフィルムの作成時または使用時に支障がない限りにおいて、例えば合成時に副生する不純物を除去することなしに用いることもできる。さらには複数種の当該化合物の混合物として用いることもできる。
【００６６】
一般式（１）で表される化合物は、先に説明した液晶性高分子に対して、０．１重量％〜２０重量％、好ましくは０．３重量％〜１０重量％添加する。添加量が０．１重量％より少ない場合、均一な配向形態を得ることができない恐れがある。一方２０重量％より多いと、耐熱性など信頼性試験において悪影響が出現する恐れがある。
【００６７】
本発明では、以上のような光学的に正の一軸性を示す液晶性高分子と一般式（１）で表される化合物を少なくとも含有する液晶性組成物を、配向基板上で均一に液晶状態、好ましくはネマチックハイブリッド配向を配向させ、続いて該配向形態を固定化せしめることで、光学素子用フィルムを製造する。そのためには以下に説明する配向基板および各工程を踏むことが望ましい。
【００６８】
先ず、配向基板について説明する。
一般に液晶性組成物を用いてネマチックハイブリッド配向を得るためには、該液晶性組成物層の上下を異なる界面で挟むことが望ましく、上下を同じ界面で挟んだ場合には、該液晶性組成物層の上下界面における配向が同一となってしまい、ネマチックハイブリッド配向を得ることが困難となってしまう。
【００６９】
本発明の光学素子用フィルムを製造するにあたって具体的な態様としては、一枚の配向基板と空気界面とを利用し、液晶性組成物層の下界面を配向基板に、また該液晶性組成物層の上界面を空気に接するようにする。上下に界面の異なる配向基板を用いることもできるが、製造プロセス上、一枚の配向基板と空気界面とを利用する方が望ましい。
【００７０】
本発明に用いることのできる配向基板は、液晶分子の傾く向き（ダイレクターの配向基板への投影）を規定できるように、異方性を有していることが望ましい。配向基板が、全く液晶の傾く向きを規定できない場合には、無秩序な方位に傾いた配向形態しか得ることができない（ダイレクターを該基板へ投影したベクトルが無秩序になる）。
【００７１】
本発明に用いることのできる配向基板として、具体的には、ポリイミド、ポリアミドイミド、ポリアミド、ポリエーテルイミド、ポリエーテルエーテルケトン、ポリエーテルケトン、ポリケトンサルファイド、ポリエーテルスルフォン、ポリスルフォン、ポリフェニレンサルファイド、ポリフェニレンオキサイド、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリエチレンナフタレート、ポリアセタール、ポリカーボネート、ポリアリレート、アクリル樹脂、ポリビニルアルコール、ポリプロピレン、セルロース系プラスチックス、エポキシ樹脂、フェノール樹脂などのプラスチックフィルム基板および一軸延伸プラスチックフィルム基板、表面にスリット状の溝を付けたアルミ、鉄、銅などの金属基板、表面をスリット状にエッチング加工したアルカリガラス、ホウ珪酸ガラス、フリントガラスなどのガラス基板、などである。
【００７２】
本発明においては上記プラスチックフィルム基板にラビング処理を施したラビングプラスチックフィルム基板、またはラビング処理を施したプラスチック薄膜、例えばラビングポリイミド膜、ラビングポリビニルアルコール膜などを有する上記各種基板、さらに酸化珪素の斜め蒸着膜などを有する上記各種基板なども用いることができる。
【００７３】
上記各種配向基板において、本発明の液晶性組成物をネマチックハイブリッド配向に形成せしめるのに好適な該基板としては、ラビングポリイミド膜を有する各種基板、ラビングポリイミド基板、ラビングポリエーテルエーテルケトン基板、ラビングポリエーテルケトン基板、ラビングポリエーテルスルフォン基板、ラビングポリフェニレンサルファイド基板、ラビングポリエチレンテレフタレート基板、ラビングポリエチレンナフタレート基板、ラビングポリアリレート基板、セルロース系プラスチック基板を挙げることができる。
【００７４】
本発明の光学素子用フィルムにおいて、液晶性組成物がネマチックハイブリッド配向を形成している場合、該フィルムの上面と下面とでは液晶性組成物のダイレクターとフィルム平面とのなす角度が異なる。該基板側のフィルム面は、その配向処理の方法や液晶性組成物の種類によって０度以上２０度以下または３０度以上９０度以下のどちらかの角度範囲に調節できる。通常、配向基板に接したフィルム界面近傍の該液晶性組成物のダイレクターとフィルム平面とのなす角度を０度以上２０度以下の角度範囲に調整する方が製造プロセス上望ましい。この場合、配向基板に接していない側のフィルム界面近傍における当該ダイレクターとフィルム平面とのなす角度は、３０度以上９０度以下の角度範囲に調整される。
【００７５】
本発明の光学素子用フィルムは、上記の如き配向基板上に均一に液晶性組成物を塗布し、次いで均一配向過程、配向形態の固定化過程を経て得られる。該液晶性組成物の配向基板への塗布は、通常液晶性組成物を各種溶媒に溶解した溶液状態または該液晶性組成物を溶融した溶融状態で行うことができる。製造プロセス上、液晶性組成物を溶媒に溶解した該溶液を用いて塗布する、溶液塗布が望ましい。
溶液塗布は、先ず液晶性組成物を溶媒に溶かし、所定濃度の溶液を調製する。ここでフィルムの膜厚（液晶性高分子組成物より形成される層の膜厚）は、該液晶性組成物を基板に塗布する段階で決まるため、精密に濃度、塗布膜の膜厚などの制御をする必要がある。
【００７６】
上記溶媒としては、液晶性組成物の種類（組成比など）によって一概には言えないが、通常クロロホルム、ジクロロメタン、四塩化炭素、ジクロロエタン、テトラクロロエタン、トリクロロエチレン、テトラクロロエチレン、クロロベンゼン、オルソジクロロベンゼンなどのハロゲン化炭化水素類、フェノール、パラクロロフェノールなどのフェノール類、ベンゼン、トルエン、キシレン、メトキシベンゼン、１，２−ジメトキベンゼンなどの芳香族炭化水素類、アセトン、酢酸エチル、ｔｅｒｔ−ブチルアルコール、グリセリン、エチレングリコール、トリエチレングリコール、エチレングリコールモノメチルエーテル、ジエチレングリコールジメチルエーテル、エチルセルソルブ、ブチルセルソルブ、２−ピロリドン、Ｎ−メチル−２−ピロリドン、ピリジン、トリエチルアミン、テトラヒドロフラン、ジメチルホルムアミド、ジメチルアセトアミド、ジメチルスルホキシド、アセトニトリル、ブチロニトリル、二硫化炭素など、およびこれらの混合溶媒、例えばハロゲン化炭化水素類とフェノール類との混合溶媒などが用いられる。
【００７７】
溶液の濃度は、用いる液晶性組成物の溶解性や最終的に目的とする光学素子用フィルムの膜厚に依存するため一概には言えないが、通常３〜５０重量％の範囲で使用され、好ましくは５〜３０重量％の範囲である。
また、表面張力の高い溶媒を用いる場合などにおいては塗布を安定に行うために必要であれば溶液に界面活性剤を添加することも可能である。用いることができる界面活性剤は、溶液の表面張力を下げ、塗布膜を安定化できるものであればいずれのものでも使用できるが、フッ素系界面活性剤が特に好ましく使用される。当該界面活性剤としては市販されているものを適宜使用することができ、例えばフロラード（３Ｍ社製）、ペインタッド（ダウ・コーニング社製）、サーフロン（旭硝子社製）、ユニダイン（ダイキン工業社製）、メガファック（大日本インキ社製）、エフトップ（新秋田化成社製）、フタージェント（ネオス社製）、アロン−Ｇ（東亞合成社製）、モディパー（日本油脂社製）などが挙げられる。なお本発明はこれらに限定されるものではなく、例えば同等の化学構造を持つ他社品を使用することもできることは言うまでもない。
【００７８】
上記界面活性剤の使用量は、溶液１Ｋｇに対し通常０．００１ｇ〜１ｇの範囲である。使用量が１ｇより多すぎると液晶性組成物中の異物となり欠陥の原因となる恐れがある。また配向形成に時間を要す、配向阻害を起こすなど液晶の配向形態に悪影響を与える恐れもあり望ましくない。
上記の溶媒を用いて所望の濃度に調整した液晶性組成物溶液を、上述にて説明した配向基板上に塗布する。塗布の方法としては、スピンコート法、ロールコート法、ダイコート法、プリント法、浸漬引き上げ法、カーテンコート法などを採用できる。
【００７９】
塗布後、溶媒を除去し、配向基板上に膜厚の均一な液晶性組成物の層を形成させる。溶媒除去条件は、特に限定されず、溶媒がおおむね除去でき、液晶性組成物の層が流動したり、流れ落ちたりさえしなければ良い。通常、室温での乾燥、乾燥炉での乾燥、温風や熱風の吹き付けなどを利用して溶媒を除去する。
この塗布・乾燥工程の段階は、先ず基板上に均一に液晶性組成物の層を形成させることが目的であり、該液晶性組成物は、まだ液晶配向を形成していない。次の熱処理工程により、モノドメインな液晶配向、好ましくはネマチックハイブリッド配向を完成させる。
【００８０】
熱処理によってネマチックハイブリッド配向を形成するにあたって、液晶性組成物の粘性は、界面効果による配向を助ける意味で低い方が良く、従って熱処理温度は高い方が望ましい。また液晶性組成物によっては、後述する平均チルト角が熱処理温度により異なることがある。その場合には、目的に応じた平均チルト角を得るために熱処理温度を設定する必要がある。例えば、あるチルト角を有する配向を得るために比較的低い温度で熱処理を行う必要が生じた場合、低い温度では液晶性組成物の粘性が高く、配向に要する時間が長くなる。このような場合には、一旦高温で熱処理し、モノドメインな配向を得た後に、段階的、もしくは徐々に熱処理の温度を目的とする温度まで下げる方法が有効となる。いずれにせよ、用いる液晶性組成物、具体的には液晶性高分子の特性に従い、ガラス転移点以上の温度で熱処理することが望ましい。また液晶性高分子として２種以上の組成物を本発明の液晶性組成物として供した際には、当該液晶性高分子のガラス転移点に応じて熱処理温度を設定することが望ましい。具体的には液晶性高分子を構成する２種以上の液晶性高分子化合物のうち、その中でガラス転移点の最も高い液晶性高分子化合物のガラス転移点より高温にて熱処理することが好ましい。
【００８１】
液晶配向を形成させるに要する熱処理温度は、通常５０〜３００℃、好ましくは７０〜２８０℃、さらに好ましくは１００〜２６０℃の範囲である。また上記にて説明したように複数の温度で連続して熱処理する、すなわち一旦ある温度で熱処理した後、該温度より低温または高温で熱処理することも本発明では可能である。
また配向基板上において、液晶性組成物が十分な配向をするために必要な熱処理時間は、用いる液晶性組成物の種類（例えば組成比など）、熱処理温度によって異なるため一概にはいえないが、通常１０秒〜１２０分、好ましくは３０秒〜６０分の範囲が好ましい。１０秒より短い場合は配向が不十分となる恐れがある。また１２０分より長い場合は、生産性が低下する恐れがあり望ましくない。
【００８２】
このようにして、まず液晶状態で配向基板上全面にわたって均一なネマチックハイブリッド配向を得ることができる。
なお、本発明においては上記の熱処理工程において磁場や電場を利用しても差し支えない。しかし熱処理しつつ余りに強力な磁場や電場を印加した場合、印加中は均一な場の力が液晶性組成物に働くために、該液晶のダイレクターは一定の方向を向きやすくなる。すなわち、本発明の如くダイレクターがフィルムの膜厚方向によって異なる角度を形成しているネマチックハイブリッド配向は得られ難くなる。
【００８３】
こうして液晶性組成物の液晶状態において形成したネマチックハイブリッド配向を、次に該液晶性組成物の液晶転移点以下の温度に冷却することにより、該配向の均一性を全く損なわずに固定化することができる。一般的にネマチック相より低温部にスメクチック相または結晶相を持っている液晶性組成物を用いた場合、液晶状態におけるネマチック配向は冷却することによって壊れてしまう恐れがある。本発明においては、
▲１▼ ネマチック相を示す温度領域より下の温度においてスメクチック相または結晶相を全く有しない、
▲２▼ 潜在的に結晶相またはスメクチック相を有していても冷却時にはスメクチック相または結晶相が現れない性質を持ち、
かつ
▲３▼ 光学素子用フィルムの使用温度範囲において流動性がなく外場や外力を加えても配向形態が変化しない、
といった性質を有する液晶性組成物を用いるため、スメクチック相または結晶相への相転移による配向形態の破壊は起こらず、完全にモノドメインな液晶配向、好ましくはネマチックハイブリッド配向を固定化することができる。
【００８４】
上記冷却温度は、液晶転移点以下の温度であれば特に制限はない。例えば液晶転移点より１０℃低い温度において冷却することにより、均一な液晶配向を固定化することができる。冷却の手段は、特に制限はなく、熱処理工程における加熱雰囲気中から液晶転移点以下の雰囲気中、例えば室温中に出すだけで固定化することができる。また生産の効率を高めるために、空冷、水冷などの強制冷却、除熱を行ってもよい。ただし液晶性組成物によっては、冷却速度の影響で得られる平均チルト角が若干異なることがある。このような液晶性組成物を使用し、厳密に平均チルト角を制御する必要が生じた際には、冷却操作も適宜冷却条件を考慮して行うことが望ましい。
【００８５】
次いで、本発明においてネマチックハイブリッド配向のフィルム膜厚方向における角度制御について説明する。本発明の光学素子用フィルムではネマチックハイブリッド配向を固定化した際、当該フィルム界面近傍における液晶性組成物のダイレクターとフィルム平面との成す角度の絶対値が、該フィルムの上面または下面の一方においては、０度以上２０度以下の範囲内、また当該面の反対面では３０度以上９０度以下の範囲である。使用する液晶性組成物の種類や組成比、配向基板および熱処理条件などを適宜選択することにより、所望の角度にそれぞれ制御することができる。またネマチックハイブリッド配向を固定化した後でも、例えばフィルム表面を均一に削る、溶剤に浸してフィルム表面を均一に溶かす、などといった方法を用いることにより所望の角度に制御することも可能である。なおこの際に用いられる溶剤は、液晶性組成物の種類や組成比、配向基板の種類によって適宜選択する必要がある。
【００８６】
以上の工程によって得られる本発明の光学素子用フィルムは、ネマチックハイブリッド配向という配向形態を均一に配向・固定化したものを得ることができる。また該配向を形成しているので、該フィルムの上下は等価ではなく、また面内方向にも異方性がある。したがって該フィルムを液晶表示素子用の視野角改良フィルムとして利用し、該フィルムをＬＣＤに配置することによって様々な特性を引き出すことが可能となる。
【００８７】
以下に本発明の光学素子用フィルムを視野角改良フィルムとして用いる方法についてさらに詳細に説明する。
視野角改良フィルムをツイステッドネマチック型液晶セルに配置する場合、該フィルムの使用形態として
▲１▼上述の配向基板を該フィルムから剥離して、視野角改良フィルム単体で用いる、
▲２▼配向基板上に形成したそのままの状態で用いる、
▲３▼配向基板とは異なる別の基板に視野角改良フィルムを積層して用いる、
ということが可能である。
【００８８】
フィルム単体として用いる場合には、配向基板を視野角改良フィルムとの界面で、ロールなどを用いて機械的に剥離する方法、構造材料すべてに対する貧溶媒に浸漬した後、機械的に剥離する方法、貧溶媒中で超音波をあてて剥離する方法、配向基板と該フィルムとの熱膨張係数の差を利用して温度変化を与えて剥離する方法、配向基板そのものまたは配向基板上の配向膜を溶解除去する方法などによってフィルム単体を得ることができる。剥離性は、用いる液晶性組成物の種類と配向基板との密着性によって異なるため、その系に最も適した方法を採用すべきである。なお視野角改良フィルム単体で用いる場合、膜厚によっては自己支持性を有しない場合があるが、その際には光学性質上好ましい基板、例えばポリメタクリレート、ポリカーボネート、ポリビニルアルコール、ポリエーテルスルフォン、ポリスルフォン、ポリアリレート、ポリイミド、アモルファスポリオレフィン、トリアセチルセルロースなどのプラスチック基板上に接着剤または粘着剤を介して固定して用いるほうが、当該フィルムの強度、信頼性などのために望ましい。
【００８９】
次に配向基板上に形成した状態で視野角改良フィルムを用いる場合について説明する。配向基板が透明で光学的に等方であるか、あるいは配向基板がＴＮ−ＬＣＤにとって必要な部材である場合には、そのまま目的とする補償素子としてＴＮ−ＬＣＤに組み込むことができる。
【００９０】
さらに配向基板上で液晶性組成物を配向固定化して得られた本発明の視野角改良フィルムを該基板から剥離して、光学用途により適した別の基板上に積層して用いる場合について説明する。すなわち本発明の視野角改良フィルムは、配向基板とは異なる別の基板とから少なくとも構成される積層体を補償素子としてＴＮ−ＬＣＤに組み込むことができる。例えば使用する配向基板がネマチックハイブリッド配向を得るために必要なものではあるが、ＴＮ−ＬＣＤに対して好ましくない影響を与えるような該基板を用いた場合、その基板を配向固定化後の視野角改良フィルムから除去して用いることができる。具体的には次のような方法を採ることができる。
【００９１】
目的とするＴＮ−ＬＣＤに組み込む液晶表示素子に適した基板（以下、第２の基板という）と配向基板上の視野角改良フィルムとを、例えば接着剤または粘着剤を用いて貼りつける。次いで配向基板を視野角改良フィルムとの界面で剥離し、当該フィルムを液晶表示素子に適した第２の基板側に転写して補償素子を得ることができる。
【００９２】
転写に用いられる第２の基板としては、適度な平面性を有するものであれば特に限定されないが、ガラス基板や透明で光学的等方性を有するプラスチックフィルムが好ましく用いられる。かかるプラスチックフィルムの例としては、ポリメチルメタクリレート、ポリスチレン、ポリカーボネート、ポリエーテルスルフォン、ポリフェニレンサルファイド、ポリアリレート、アモルファスポリオレフィン、トリアセチルセルロースまたはエポキシ樹脂などを挙げることができる。なかでもポリメチルメタクリレート、ポリカーボネート、ポリアリレート、ポリエーテルスルフォン、トリアセチルセルロースなどが好ましく用いられる。また光学的に異方性であっても、ＴＮ−ＬＣＤにとって必要な部材である場合には、光学的異方性フィルムなども用いることができる。光学的異方性フィルムとしては、例えばポリカーボネートやポリスチレンなどのプラスチックフィルムを延伸して得られる位相差フィルム、偏光フィルムなどが挙げられる。
【００９３】
さらに、用いられる第２の基板の例として液晶セルそのものを挙げることができる。液晶セルは、上下２枚の電極付きガラスまたはプラスチック基板を用いており、この上下いずれか、あるいは両面のガラスまたはプラスチック基板上に本発明の視野角改良フィルムを転写すれば、当該フィルムの組み込みがすでに達成されたことになる。また液晶セルを形成するガラスまたはプラスチック基板そのものを配向基板として本発明の視野角改良フィルムを製造することももちろん可能である。
以上説明した第２の基板は、液晶性組成物の配向制御能を実質的に持つ必要はない。また、第２の基板と該フィルムとの間に配向膜などは必要としない。
【００９４】
転写に用いられる第２の基板と、本発明の視野角改良フィルムとを貼り付ける接着剤または粘着剤は、光学グレードのものであれば特に制限はないが、アクリル系、エポキシ系、エチレン−酢酸ビニル共重合体系、ゴム系、ウレタン系、およびこれらの混合系などを用いることができる。また接着剤としては、熱硬化型、光硬化型、電子線硬化型などのいずれの接着剤でも光学的等方性を有していれば問題なく使用することができる。
【００９５】
本発明の視野角改良フィルムを液晶表示素子に適した第２の基板への転写は、接着後、配向基板を該フィルムとの界面で剥離することにより行える。剥離の方法は、上述でも説明したが、ロールなどを用いて機械的に剥離する方法、構造材料すべてに対する貧溶媒に浸漬したのち機械的に剥離する方法、貧溶媒中で超音波をあてて剥離する方法、配向基板と該フィルムとの熱膨張係数の差を利用して温度変化を与えて剥離する方法、配向基板そのものまたは配向基板上の配向膜を溶解除去する方法などを例示することができる。剥離性は、用いる液晶性組成物の種類と配向基板との密着性によって異なるため、その系に最も適した方法を採用すべきである。
また本発明の視野角改良フィルムは、表面保護、強度増加、環境信頼性向上などの目的のために透明プラスチックフィルムなどの保護層を設けることもできる。
【００９６】
このようにして得られた視野角改良フィルムは、ＴＮ−ＬＣＤに対して特に優れた視野角補償効果をもつ。本発明のフィルムが各種ＴＮ−ＬＣＤに対して、より好適な補償効果を発現するための当該フィルム膜厚としては、対象とするＴＮ−ＬＣＤの方式や種々の光学パラメーターに依存するので一概には言えないが、通常０．１μｍ以上２０μｍ以下、好ましくは０．２μｍ以上１０μｍ以下の範囲、さらに好ましくは０．３μｍ以上５μｍ以下の範囲である。膜厚が０．１μｍ未満の時は、十分な補償効果が得られない恐れがある。また膜厚が２０μｍを越えるとディスプレーの表示が不必要に色づく恐れがある。
ただし本発明の視野角改良フィルムの性能をより高く引き出すためには、当該フィルムの光学パラメーターや軸配置をさらに詳細に考慮することが望ましい。
【００９７】
以下個々に説明する。
先ず、視野角改良フィルムの法線方向から見た場合における面内の見かけのリターデーション値について説明する。ネマチックハイブリッド配向したフィルムでは、ダイレクターに平行な方向の屈折率（以下ｎｅと呼ぶ）と垂直な方向の屈折率（以下ｎｏと呼ぶ）が異なっている。ｎｅからｎｏを引いた値を見かけ上の複屈折率とした場合、見かけ上のリターデーション値は見かけ上の複屈折率と絶対膜厚との積で与えられる。この見かけ上のリターデーション値は、エリプソメトリー等の偏光光学測定により容易に求めることができる。本発明の視野角改良フィルムにおける見かけ上のリターデーション値は、５５０ｎｍの単色光に対して、通常５ｎｍ〜５００ｎｍの範囲、好ましくは１０ｎｍ〜３００ｎｍの範囲、さらに好ましくは１５ｎｍ〜１５０ｎｍの範囲であることが望ましい。見かけのリターデーション値が５ｎｍ未満の時は、実質的にホメオトロピック配向と何ら変わることはなく十分な視野角拡大効果が得られない恐れがある。また、５００ｎｍより大きい場合は、斜めから見たときに液晶ディスプレーに不必要な色付きが生じる恐れがある。
【００９８】
次いでダイレクターの角度について説明する。
ネマチックハイブリッド配向を固定化した視野角改良フィルムの膜厚方向におけるダイレクターの角度範囲は、フィルム界面での液晶性高分子のダイレクターと該ダイレクターのフィルム界面への投影成分がなす鋭角側の角度が、フィルムの上面または下面の一方においては、通常３０度以上９０度以下の角度をなし、当該面の反対面においては、通常０度以上２０度以下である。より好ましくは一方の角度の絶対値が４０度以上９０度以下、他方の角度の絶対値が０度以上１０度以下であることが望ましい。
【００９９】
次いで平均チルト角について説明する。
本発明においては、液晶性高分子のダイレクターと該ダイレクターの基板平面への投影成分とのなす角度の膜厚方向における平均値を平均チルト角と定義する。平均チルト角は、クリスタルローテーション法を応用して求めることができる。本発明の視野角改良フィルムの平均チルト角は、通常１０度〜６０度の範囲、好ましくは２０度〜５０度の範囲であることが望ましい。平均チルト角が１０度より小さい場合または６０度より大きい場合には、一定の視野角拡大効果は認められるものの満足できる視野角拡大効果を得ることができない恐れがある。
【０１００】
次に、本発明の視野角改良フィルムをＴＮ−ＬＣＤの視野角拡大のために用いるときの配置について具体的に説明する。本フィルムの配置位置は偏光板と液晶セルとの間であればよく、１枚または複数枚の視野角改良フィルムを配置することができる。本発明では、１枚または２枚の視野角改良フィルムを用いて補償を行うことが実用上好ましい。３枚以上の当該フィルムを用いても、補償は可能であるが、コストアップに繋がるためあまり好ましいとはいえない。具体的な配置位置を例示すると以下のようになる。ただし、これらはあくまで代表的な配置位置であり本発明はこれらに限定されるものではない。
【０１０１】
まず視野角改良フィルムの上面と下面とを次のように定義する。
光学的に正の一軸性を示す液晶性高分子のダイレクターとフィルム平面との成す角度が鋭角側で３０度以上９０度以下の角度を成している面をｂ面とする。該角度が鋭角側で０度以上２０度以下の角度を成している面をｃ面とする。
【０１０２】
次いで視野角改良フィルムのチルト方向を以下のように定義する。
当該フィルムのｂ面から液晶層を通してｃ面を見た場合、ダイレクターとダイレクターのｃ面への投影成分がなす角度が鋭角となる方向でかつ投影成分と平行な方向を視野角改良フィルムのチルト方向と定義する。
【０１０３】
次いで液晶セルのプレチルト方向を以下のように定義する。
通常液晶セル界面では、駆動用の低分子液晶は液晶セル界面に対して平行ではなく、ある角度もって傾いている。これをプレチルト角と言う。セル界面の液晶のダイレクターとダイレクターの界面への投影成分とがなす角度が鋭角である方向で、かつダイレクターの投影成分と平行な方向を該液晶セル界面のプレチルト方向と定義する。
【０１０４】
上記の定義に基づいて本視野角改良フィルム１枚をＴＮ−ＬＣＤに用いる場合について説明する。当該フィルムは偏光板と液晶セルの間に配置し、セルの上面側でも良いし下面側でも良い。視野角改良フィルムの貼合に際して、該フィルムのチルト方向と隣接しない液晶セル界面でのプレチルト方向がおおむね一致することが好ましい。チルト方向とプレチルト方向のなす角度は、絶対値として通常０度〜１５度、好ましくは０度〜１０度の範囲であり、さらに好ましくは０度〜５度の範囲である。両者のなす角度が１５度より大きい場合、十分な視野角補償効果を得ることができない恐れがある。
【０１０５】
次に、視野角改良フィルム２枚をＴＮ−ＬＣＤに用いる場合について説明する。２枚の当該フィルムは、上下一対の偏光板に挟まれた液晶セルの上面または下面に配置する。配置する際は、２枚の視野角改良フィルムが同じ側にあっても良いし、上下に各１枚ずつあっても良い。また２枚の当該フィルムは、同一のパラメータで合っても良いし、異なるものでも良い。
【０１０６】
本発明において、２枚の視野角改良フィルムを液晶セルの上下に分けて配置する場合、それぞれのフィルムを上述の１枚のみを使用する場合と同様の配置にすることが好ましい。すなわち、それぞれの視野角改良フィルム中における液晶性組成物のチトル方向と隣接しない液晶セル界面でのセル液晶のプレチルト方向がおおむね一致することが好ましい。チルト方向とプレチルト方向のなす角度は、絶対値として通常０度〜１５度、好ましくは０度〜１０度の範囲であり、さらに好ましくは０度〜５度の範囲であることが望ましい。
【０１０７】
また２枚の視野角改良フィルムを液晶セルの上面あるいは下面のどちらか一方に配置する場合、液晶セルに近い側の視野角改良フィルムを１枚の当該フィルムを用いる場合と同様の配置にする。すなわち視野角改良フィルムのチルト方向と隣接しない液晶セル界面でのネマチック液晶のプレチルト方向がおおむね一致するように配置することが好ましい。チルト方向とプレチルト方向のなす角度は、絶対値として通常０度〜１５度の範囲、好ましくは０度〜１０度の範囲、さらに好ましくは０度〜５度の範囲である。２枚目の視野角改良フィルムは、１枚目の当該フィルムと偏光板の間に配置することになるが、１枚目の当該フィルムに隣接した液晶セル界面でのネマチック液晶のプレチルト方向と２枚目の視野角改良フィルムのチルト方向がおおむね一致するように配置することが好ましい。
【０１０８】
さらに本発明の視野角改良フィルムは、ネマチックハイブリッド配向をもつために当該フィルムの上下は等価ではない。したがって当該フィルムを液晶セルに装着する場合、どちらの面を液晶セルに近い方にするかによって視野角改良効果に多少の違いが見られる。本発明の視野角改良フィルムを実際にＴＮ−ＬＣＤに組み込む際には、液晶性高分子のダイレクターがフィルム平面となす角がより大きい面（該角度が３０度以上９０度以下である面）を液晶セルに近く、偏光板から遠くなるように配置する方がより望ましい。
【０１０９】
最後に偏光板の配置について説明する。通常、ＴＮ−ＬＣＤでは上下偏光板の透過軸が互いに直交するように配置する場合と平行になるように配置する場合がある。また上下偏光板の透過軸が互いに直交する場合は、偏光板の透過軸と偏光板に近側の液晶セルのラビング方向とが平行、垂直または４５度の角度をなす場合がある。本発明の視野角改良フィルム上に偏光板を装着する場合、偏光板の配置は上記のどの配置であっても視野角改良効果は得られるが、上下偏光板の透過軸が互いに直交する配置が最も望ましい。偏光板の透過軸と該偏光板に近い側の液晶セルに施されたラビング方向との関係については視野角改良効果に多少の違いはあるものの、平行または垂直のどちらの配置とも可能である。
【０１１０】
本発明の視野角改良フィルムは、ＴＦＴ素子あるいはＭＩＭ素子を用いたＴＮ−ＬＣＤの視野角改善に絶大な効果が有り、他のモードのＬＣＤ、すなわちＳＴＮ（Ｓｕｐｅｒ Ｔｗｉｓｔｅｄ Ｎｅｍａｔｉｃ）−ＬＣＤ、ＥＣＢ（Ｅｌｅｃｔｒｉｃａｌｌｙ Ｃｏｎｔｒｏｌｌｅｄ Ｂｉｒｅｆｒｉｎｇｅｎｃｅ）−ＬＣＤ、ＯＭＩ（Ｏｐｔｉｃａｌ Ｍｏｄｅ Ｉｎｔｅｒｆｅｒｅｎｃｅ）−ＬＣＤ、ＯＣＢ（Ｏｐｔｉｃａｌｌｙ Ｃｏｍｐｅｎｓａｔｅｄ Ｂｉｒｅｆｒｉｎｇｅｎｃｅ）−ＬＣＤ、ＨＡＮ（Ｈｙｂｒｉｄ Ａｌｉｇｎｅｄ Ｎｅｍａｔｉｃ）−ＬＣＤ、ＩＰＳ（Ｉｎ Ｐｌａｎｅ Ｓｗｉｔｃｈｉｎｇ）−ＬＣＤなどの色補償、視野角改良にも有効である。
【０１１１】
以上本発明の光学素子用フィルムは、耐熱性、耐湿性および耐光性などの信頼性を十分に満足するものであり、またフィルム強度も強い。さらには配向処理にあたり広範な条件で配向が可能であり、ムラ・配向欠陥の極めて少ない当該フィルムを工業的に得ることができるなど、その工業的利用価値は極めて高い。
【０１１２】
【実施例】
以下に実施例を述べるが、本発明はこれらに制限されるものではない。なお実施例で用いた各分析法は以下の通りである。
（１）液晶性高分子の組成決定および化合物の構造決定
重水素化クロロホルムまたは重水素化トリフルオロ酢酸に溶解し、４００ＭＨｚの ¹Ｈ−ＮＭＲ（日本電子製ＪＮＭ−ＧＸ４００）を用いて決定した。
（２）対数粘度の測定
ウベローデ型粘度計を用い、フェノール／テトラクロロエタン（６０／４０重量比）混合溶媒中、３０℃で測定した。
（３）液晶相系列の決定
ＤＳＣ（Ｐｅｒｋｉｎ Ｅｌｍｅｒ ＤＳＣ−７）測定および光学顕微鏡（オリンパス光学（株）製ＢＨ２偏光顕微鏡）観察により決定した。
（４）屈折率の測定
アッベ屈折計（アタゴ（株）製Ｔｙｐｅ−４）により屈折率を測定した。
（５）偏光解析
（株）溝尻光学工業製エリプソメーターＤＶＡ−３６ＶＷＬＤを用いて行った。
（６）膜厚測定
ＳＬＯＡＮ製ＳＵＲＦＡＣＥ ＴＥＸＴＵＲＥ ＡＮＡＬＹＳＩＳ ＳＹ−ＳＴＥＭ Ｄｅｋｔａｋ ３０３０ＳＴを用いた。また、干渉波測定（日本分光（株）製 紫外・可視・近赤外分光光度計Ｖ−５７０）と屈折率のデータから膜厚を求める方法も併用した。
【０１１３】
参考例１
テレフタル酸４０ｍｍｏｌ、２，６−ナフタレンジカルボン酸４０ｍｍｏｌ、カテコールジアセテート８５ｍｍｏｌ、アセトキシ安息香酸８０ｍｍｏｌを用いて窒素雰囲気下２６０℃で４時間、２９０℃で２時間、続いて毎分１００ｍｌの窒素気流下２９０℃で４時間重合を行い、液晶性ポリエステル（式１）を得た。この液晶性ポリエステルの対数粘度は０．１６、液晶相としてネマチック相をもち、等方相−液晶相転移温度は３００℃以上、ガラス転移点は１２０℃であった。該液晶性ポリエステルを用い１０ｗｔ％のフェノール／テトラクロロエタン混合溶媒（６／４重量比）溶液を調製した。この溶液を、ソーダガラス板上に、バーコート法により塗布し、乾燥し、１９０℃で３０分熱処理したのち、室温下で冷却・固定化し、膜厚１μｍの液晶性フィルムを得た。該フィルムの偏光顕微鏡下の観察により隣接するドメインの消光軸が同一でありながらディスクリネーションラインが存在する部分を見いだしチルト配向性であることを確認した。
【０１１４】
【化１２】

【０１１５】
参考例２
４−オクチロキシ安息香酸１０ｍｍｏｌ、テレフタル酸５０ｍｍｏｌ、ナフタレンジカルボン酸４５ｍｍｏｌ、カテコールジアセテート５０ｍｍｏｌ、３−メチルカテコールジアセテート５０ｍｍｏｌ、４−アセトキシ安息香酸５０ｍｍｏｌを用いて窒素雰囲気下、２７０℃で４時間、続いて同温度で毎分３０ｍｌの窒素気流下で２時間脱酢酸重合を行った。次に得られた反応生成物をテトラクロロエタンに溶解したのち、メタノールで再沈澱を行って精製し、液晶性ポリエステル（式２）を得た。この液晶性ポリエステルの対数粘度は０．１０、液晶相としてネマチック相をもち、等方相−液晶相転移温度は２４０℃、ガラス転移点は７５℃であった。
【０１１６】
該液晶性ポリエステルを用い１０ｗｔ％のフェノール／テトラクロロエタン混合溶媒（６／４重量比）溶液を調製した。この溶液を、ソーダガラス板上に、スピンコート法により塗布し、乾燥し、２２０℃で３０分熱処理したのち、室温下で冷却・固定化し、膜厚１０μｍの均一配向フィルムを得た。該フィルムのコノスコープ観察により、該フィルムがホメオトロピック配向フィルムであることを確認した。
【０１１７】
【化１３】

【０１１８】
参考例３
ｔｅｒｔ−ブチルハイドロキノンジアセテート１０ｍｍｏｌ、６−ペンチロキシ−２−ナフトエ酸２０ｍｍｏｌを窒素雰囲気下２５０℃で４時間、２７０℃で２時間、続いて毎分３０ｍｌの窒素気流下２７０℃で２時間反応させた。続いて該化合物をメタノール／酢酸エチル＝１／１の混合溶媒から再結晶して式（３）の化合物を得た。
【０１１９】
【化１４】

【０１２０】
実施例１
参考例で得られた液晶性ポリエステル（式１）７５部、液晶性ポリエステル（式２）２０部、および化合物（式３）５部を配合して液晶性組成物を調整した。次いで当該組成物の８ｗｔ％テトラクロロエタン溶液を調製した。当該溶液をラビングポリイミド膜を有するガラス基板上にスピンコート法により塗布し、乾燥し、２２０℃で２０分間熱処理した。熱処理後、空冷しフィルム１を得た。得られたガラス基板上のフィルム１は透明で配向欠陥はなく均一で膜厚は１．５５μｍであった。
【０１２１】
図１、図２に示した光学測定系を用いて、フィルム１を基板のラビング方向に傾けていき、リターデーション値を測定した。その結果、図３のような左右非対称でかつリターデーション値が０になる角度がない結果が得られた。この結果から、液晶性ポリエステルのダイレクターが基板に対して傾いており均一チルト配向（ダイレクターと基板表面のなす角が膜厚方向で一定な配向状態）ではないことが判明した。
【０１２２】
次いで基板上の該フィルム１を５枚に切り分け、それぞれ一定時間クロロホルムを３ｗｔ％含むメタノール溶液に浸漬し、液晶層上面より溶出させた。浸漬時間を１５秒、３０秒、１分、２分、５分とした場合に、溶出せずに残った液晶層の膜厚は、それぞれ１．３５μｍ、１．１０μｍ、０．８８μｍ、０．５６μｍ、０．３７μｍであった。図１、図２の光学系を用いてθ＝０度の場合のリターデーション値（正面リターデーション値）を測定し、図４の膜厚とリターデーション値の関係を得た。図４から分かるように膜厚とリターデーション値は直線関係にはなく、このことからも均一チルト配向ではないことが判明した。図中の点線は、均一チルト配向したフィルムにおいて通常観測される直線である。
【０１２３】
次に、該液晶性組成物をラビングポリイミド膜を有する高屈折率ガラス基板（屈折率は１．８４）上に、上記と同様な方法を用いて配向・固定化し、フィルム１’を作製し、当該フィルムを用いて屈折率測定を行った。屈折計のプリズム面にガラス基板が接するように置き、フィルム１’の基板界面側が空気界面側より下にくるように配置した場合、フィルム面内の屈折率には異方性が有りラビング方向に垂直な面内の屈折率は１．５５、平行な面内の屈折率は１．７１であり、膜厚方向の屈折率はフィルム２の方向によらず１．５５で一定であった。このことから、ガラス基板側では液晶性ポリエステルを構成する棒状の液晶分子が基板に対して平行に平面配向していることが分かった。次に屈折率計のプリズム面にフィルム１’の空気界面側が接するように配置した場合、面内の屈折率には異方性がなく屈折率は１．５５と一定であった。また膜厚方向の屈折率はフィルム１’の方向によらず１．７１と一定であり、このことから空気界面側では液晶性ポリエステルを構成する棒状の液晶分子が基板平面に対して垂直に配向していることが判明した。
【０１２４】
以上のことより本実施例で得られたフィルムは、ネマチックハイブリッド配向を形成しており、ラビングによる基板界面の規制力および空気界面の規制力によって、図５に示したように配向していることが判明した。
【０１２５】
次に、基板界面におけるダイレクターの方位の角度をより正確に求めるため、以下の操作を行った。
上記のラビングポリイミド膜を有する高屈折ガラス基板上に形成されたフィルム１’の上に、もう一枚ラビングポリイミド膜を有するガラス基板をかぶせ密着させた。すなわちフィルム１’を２枚のラビングポリイミド膜で挟んだ構成にした。この時、上下のラビング膜のラビング方向が互いの１８０度になるように配置した。この状態において１９０℃、３０分間熱処理した。こうして得られた試料フィルムについて屈折率測定および偏光解析を行った。屈折率測定の結果、試料フィルムの上下に関して同じ値が得られ、該フィルム面内の屈折率はラビング方向に垂直な面内では１．５５、平行な面内では１．７１、該フィルムの膜厚方向では１．５５であった。このことから基板の界面付近では試料フィルムの上下ともにダイレクターが基板平面に対して略平行であることが判明した。さらに偏光解析の結果、屈折率構造はほぼ正の一軸性であり、クリスタルローテーション法に基づき詳細な解析を行った結果、基板界面付近では、わずかにダイレクターの傾きがあり、基板平面とダイレクターのなす角度は約３度であった。また、ダイレクターの傾く向きはラビング方向と一致していた（フィルムのチルト方向とラビング方向とは一致する）。
【０１２６】
以上のことより、基板界面におけるダイレクターの方位は、液晶性高分子と配向基板界面の相互作用によってほぼ決まると考えると、前述の一枚の配向基板上に形成されたフィルム１およびフィルム１’のネマチックハイブリッド配向における基板界面でのダイレクターの方位は３度であると推定される。
【０１２７】
実施例２
実施例１と同一の液晶組成物を用いて８ｗｔ％テトラクロロエタン溶液を調製した。該溶液をラビングポリイミド膜を有するガラス基板上にスピンコート法により塗布し、乾燥した。次いで２１０℃で１０分間熱処理したのち、冷却しフィルム２を得た。基板上のフィルム２は透明で配向欠陥はなく均一であった。また膜厚は０．４２μｍ、膜厚方向の平均チルト角は３６度であった。
【０１２８】
フィルム２を２枚使用し、各光学素子を図６に示した軸配置でもって配置した。このときフィルム２の空気界面側が液晶セルに近い側になるように、液晶セルの上下にフィルム２を各１枚ずつ配置した。使用した液晶セルは液晶材料としてＺＬＩ−４７９２を用い、セルパラメータはセルギャップ４．８μｍ、ねじれ角９０度（左ねじれ）、プレチルト角４度である。液晶セルに対して、３００Ｈｚの矩形波で電圧を印加した。白表示０Ｖ、黒表示６Ｖの透過率の比（白表示）／（黒表示）をコントラスト比として、全方位からのコントラスト比測定を浜松ホトニクス（株）製品ＦＦＰ光学系ＤＶＳ−３０００を用いて行い、等コントラスト曲線を描いた。その結果を図７に示す。
図６の配置において白表示と黒表示の透過率の差を８等分するような電圧を液晶セルに印加し横方向（０度−１８０度方向）での階調特性について（株）トプコン社製色彩輝度計ＢＭ−５を用いて測定した。結果を図８に示す。
【０１２９】
比較例１
実施例２と同じＴＮ型液晶セルを用いて、フィルム２を装着しない以外は全て同じ条件にて全方位でのコントラスト比測定、横方向（０度−１８０度方向）での階調特性の測定を行った。結果を図９、図１０に示す。
【０１３０】
参考例４
４−（２−エチルヘキシロキシ）フェノール２２ｍｍｏｌをピリジン５００ｍｌに溶解し、メカニカルスターラーにより攪拌しながら０℃においてテレフタル酸ジクロライド１０ｍｍｏｌを２００ｍｌの塩化メチレンに溶かした溶液を３０分かけて滴下した。０℃で２時間、室温で５時間反応させた後、ピリジンを減圧下留去した。残渣に、１Ｎ塩酸５００ｍｌを加え、酢酸エチルで抽出した。抽出液を再度１Ｎ塩酸で洗浄した後、水、重曹水、飽和食塩水を順番に用いて洗浄した。次いで抽出液を硫酸マグネシウムで乾燥した後、溶媒を留去、続いて残渣をメタノール／酢酸エチルの混合溶媒から再結晶し、式４の化合物を得た。
【０１３１】
【化１５】

【０１３２】
実施例３
参考例で得られた液晶性ポリエステル（式１）７０部、液晶性ポリエステル（式２）２７部、および化合物（式４）３部を配合して液晶性組成物を調整した。次いで当該組成物の１０ｗｔ％Ｎ−メチルピロリドン溶液を調製した。さらに溶液の表面張力を低下させるために界面活性剤としてＫＨ−４０（旭硝子社製）を溶液全重量に対し０．００５％添加した。
実施例２と同一の条件で塗布、乾燥、熱処理を行いフィルム３を得た。フィルム３は膜厚０．５０μｍ、膜厚方向の平均チルト角は３０度であった。当該フィルムを用い、実施例２と同様の方法により全方位からのコントラスト比測定を行った。その結果を図１１に示す。
【０１３３】
参考例５
４−ベンジロキシ安息香酸２０ｍｍｏｌとカテコールジアセテート１０ｍｍｏｌを用いて窒素雰囲気下、２７０℃、４時間、続いて同温度で毎分３０ｍｌの窒素気流下で２時間脱酢酸反応を行った。得られた反応生成物をテトラクロロエタンに溶解した後、メタノールで再沈澱を行い、式５の化合物を得た。
【０１３４】
【化１６】

【０１３５】
次いで当該化合物を酢酸エチル５００ｍｌに溶解し、１ｇの５％Ｐｄ／Ｃ触媒と共に室温で２４時間、２気圧の水素雰囲気下水素化分解反応に供しベンジル基を脱離させた。続いて反応性生成物をジメチルアミノピリジン１ｇを加えた塩化メチレン５００ｍｌとピリジン１００ｍｌの混合物に溶解し、０℃において４−オクチルオキシ安息香酸クロライド２０ｍｍｏｌを塩化メチレン２００ｍｌに溶解した溶液を３０分かけて滴下した。０℃で２時間、室温で５時間反応させた後、ピリジンを減圧下留去した。残渣に、１Ｎ塩酸５００ｍｌを加え、酢酸エチルで抽出した。抽出液を再度１Ｎ塩酸で洗浄した後、水、重曹水、飽和食塩水を順番に用いて洗浄した。次いで抽出液を硫酸マグネシウムで乾燥した後、溶媒を留去、続いて残渣をクロロホルムに溶解し、該溶液をメタノールに再沈することにより式６の化合物を得た。
【０１３６】
【化１７】

【０１３７】
参考例６
２−ベンジロキシフェノール２０ｍｍｏｌをピリジン５００ｍｌに溶解し、メカニカルスターラーにより攪拌しながら０℃において４，４’−オキシビス（安息香酸ジクロライド）１０ｍｍｏｌを２００ｍｌの塩化メチレンに溶解した溶液を３０分かけて滴下した。０℃で２時間、室温で５時間反応させた後、ピリジンを減圧下留去した。残渣に１Ｎ塩酸を５００ｍｌ加え、酢酸エチルで抽出した。抽出液を再度１Ｎ塩酸で洗浄した後、水、重曹水、飽和食塩水を順に用いて洗浄した。次いで抽出液を硫酸マグネシウムで乾燥した後、溶媒を留去した。得られた残渣をメタノール／酢酸エチルの混合溶媒を用いて再結晶し、式７の化合物を得た。
【０１３８】
【化１８】

【０１３９】
次いで当該化合物を酢酸エチル５００ｍｌに溶解し、１ｇの５％Ｐｄ／Ｃ触媒と共に室温で２４時間、２気圧の水素雰囲気下水素化分解反応に供しベンジル基を脱離させた。続いて反応性生成物をジメチルアミノピリジン１ｇを加えた塩化メチレン５００ｍｌとピリジン１００ｍｌの混合物に溶解し、０℃において４’−ブトキシスチルベン−４−カルボン酸クロライド２０ｍｍｏｌを塩化メチレン２００ｍｌに溶解した溶液を３０分かけて滴下した。０℃で２時間、室温で５時間反応させた後、ピリジンを減圧下留去した。残渣に、１Ｎ塩酸５００ｍｌを加え、酢酸エチルで抽出した。抽出液を再度１Ｎ塩酸で洗浄した後、水、重曹水、飽和食塩水を順番に用いて洗浄した。次いで抽出液を硫酸マグネシウムで乾燥した後、溶媒を留去、続いて残渣をＮ−メチルピロリドンに溶解し、該溶液をメタノールに再沈することにより式８の化合物を得た。
【０１４０】
【化１９】

【０１４１】
参考例７〜１８
表１中Ｘの化合物を１０ｍｍｏｌ、表１中Ｙの化合物を２０ｍｍｏｌ混合し、窒素雰囲気下２５０℃で４時間、２７０℃で２時間、続いて毎分３０ｍｌの窒素気流下２７０℃で２時間反応させた。化合物（１１）、（１３）、（１５）、（１６）、（１７）、（２０）についてはさらにメタノール／酢酸エチル＝１／１の混合溶媒から再結晶して精製した。一方、化合物（９）、（１０）、（１２）、（１４）、（１８）、（１９）については、粗生成物をクロロホルムに溶解した後メタノールに滴下し生成物を再沈させることにより精製した。
【０１４２】
【表１】

【０１４３】
【化２０】

【０１４４】
【化２１】

【０１４５】
【化２２】

【０１４６】
参考例１９〜２５
表２中Ｘで示される化合物２０ｍｍｏｌをピリジン５００ｍｌに溶解し、メカニカルスターラーにより攪拌しながら０℃において表２中Ｙで示される化合物１０ｍｍｏｌを２００ｍｌの塩化メチレンに溶解した溶液を３０分かけて滴下した。０℃で２時間、室温で５時間反応させた後、ピリジンを減圧下留去した。残渣に１Ｎ塩酸を５００ｍｌ加え、酢酸エチルで抽出した。抽出液を再度１Ｎ塩酸で洗浄した後、水、重曹水、飽和食塩水を順に用いて洗浄した。次いで抽出液を硫酸マグネシウムで乾燥した後、溶媒を留去した。
【０１４７】
この後、化合物（２１）、（２３）、（２５）、（２６）、（２７）についてはメタノール／酢酸エチル＝１／１の混合溶媒から再結晶して精製した。一方、化合物（２２）、（２４）については、粗生成物をクロロホルムに溶解した後メタノールに滴下し生成物を再沈させることにより精製した。
【０１４８】
【表２】

【０１４９】
【化２３】

【０１５０】
【化２４】

【０１５１】
実施例４〜３４
実施例３と同様な方法にてフィルムを作成し、当該フィルムをそれぞれ評価した結果を表３に示した。
【０１５２】
【表３】

【図面の簡単な説明】
【図１】本発明の光学素子用フィルムのチルト角測定に用いた光学測定系の配置図を示す。
【図２】本発明の光学素子用フィルムのチルト角測定に用いた光学測定系の試料および偏光板の軸方位の関係を示す。
【図３】実施例１において、基板のラビング方向に沿って傾けて測定した見かけのリターデーション値と試料（フィルム１）の傾き角の関係を示す。
【図４】実施例１において、フィルム１の浸漬後の膜厚と試料の正面での見かけのリターデーション値の測定結果を示す。
【図５】実施例１で得られたフィルム１の配向構造の概念図である。
【図６】実施例２における各光学素子の軸配置を示す。
【図７】実施例２の等コントラスト曲線を示す。
【図８】実施例２の横方向での階調特性の測定結果を示す。
【図９】比較例１の等コントラスト曲線を示す。
【図１０】比較例１の横方向での階調特性を示す。
【図１１】実施例３の等コントラスト曲線を示す。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a film for optical elements in which the orientation of a liquid crystalline polymer composition exhibiting optically positive uniaxiality is fixed, and more particularly to a viewing angle improving film and a twisted nematic liquid crystal display device including the film. .
[0002]
[Prior art]
An active-driven twisted nematic liquid crystal display device (hereinafter abbreviated as TN-LCD) using TFT elements or MIM elements, when viewed from the front, in addition to the LCD's original features of thinness, light weight, and low power consumption. Since it has an image quality comparable to that of a CRT, it is widely used as a display device such as a notebook personal computer, a portable television, and a portable information terminal. However, in the conventional TN-LCD, since the refractive index anisotropy of the liquid crystal molecules, the viewing angle problem that the display color changes or the display contrast decreases when viewed from an oblique direction is unavoidable. The improvement is strongly desired, and various attempts have been made for improvement.
[0003]
A method of dividing one pixel and changing the applied voltage to each pixel at a constant ratio (halftone gray scale method), a method of dividing one pixel and changing the rising direction of liquid crystal molecules in each pixel ( Domain splitting method), method of applying lateral electrolysis to liquid crystal (IPS method), method of driving vertically aligned liquid crystal (VA liquid crystal method), method of combining bend alignment cell and optical compensator (OCB method), etc. Liquid crystal display devices using these have been developed and prototyped.
[0004]
However, although these methods have certain effects, it is necessary to change the alignment film, electrodes, liquid crystal alignment, etc., and it is necessary to establish a manufacturing technique and newly set up manufacturing equipment, resulting in manufacturing difficulty and high cost. Invited.
On the other hand, there is a method of expanding the viewing angle by incorporating an optical compensation film into a conventional TN-LCD without changing the structure of the TN-LCD. This method is attracting attention because it does not require improvement or expansion of TN-LCD manufacturing equipment, is excellent in cost, and has an advantage that it can be used easily.
[0005]
As an example of conditions required for the film material in producing the film as described above,
1) Reliable enough for commercialization in terms of heat resistance, moisture resistance, light resistance, etc.
2) Alignment is possible under a wide range of conditions for alignment treatment, and products with less unevenness and alignment defects can be obtained.
3) Strong film strength and sufficient impact resistance and handling
Can be mentioned.
However, it has been difficult to sufficiently satisfy all the above requirements when manufactured using a conventionally known film material. Therefore, it has been necessary to develop a material system that satisfies the above requirements without deteriorating the optical performance of the film.
[0006]
[Problems to be solved by the invention]
The present invention solves the above-described problems. Specifically, by forming and fixing the alignment using a liquid crystalline polymer blended with a specific compound, it is excellent in reliability and strength, and has good quality with few defects and unevenness. It is providing the film for optical elements.
[0007]
[Means for Solving the Problems]
That is, the first aspect of the present invention is a main chain atom in which a liquid crystalline polymer (a) exhibiting optically positive uniaxial properties and a plurality of alicyclic rings and / or aromatic rings are bonded to different ring carbon atoms. The molecular weight is 1000 linked through several linking chains of 0 to 4, and each terminal ring is bonded with a hydrocarbon group having 1 to 20 carbon atoms via a linking chain having 0 to 4 main chain atoms. An optical element film characterized in that it is formed of a liquid crystalline composition containing at least the following polycyclic compound (b), and the alignment form formed in the liquid crystal state of the liquid crystalline composition is fixed. .
A second aspect of the present invention is the above film for an optical element, wherein the orientation form is nematic hybrid orientation.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The film for optical elements of the present invention can be used for various optical element applications depending on the orientation of polymer liquid crystals that determine the optical properties of the film. For example, it can be suitably used as an optical functional film represented by a viewing angle improving film, a color compensation film, and a polarizing film. Among them, the film for optical elements in which the nematic hybrid alignment form is fixed can be suitably used as a viewing angle improving film for TN-LCD, and the viewing angle dependence of TN-LCD can be greatly improved.
[0009]
The TN-LCD to be compensated will be described. If the TN-LCD is classified according to a driving method, a simple matrix method, a TFT (Thin Film Transistor) electrode using an active element as an electrode, a MIM (Metal Insulator Metal, or TFD; Thin) It can be subdivided like an active matrix system using a film diode). The viewing angle improving film of the present invention has a remarkable viewing angle improving effect for any driving method.
The halftone gray scale method (pixel division method) and the domain division method, which are known techniques, are attempts to increase the viewing angle of the LCD from the liquid crystal cell side. The viewing angle improving film of the present invention works effectively even for an LCD having such a viewing angle improved to some extent, and a further viewing angle widening effect is possible.
[0010]
The film is preferably a film in which a nematic hybrid alignment state is fixed. Here, the nematic hybrid alignment refers to an alignment form in which the liquid crystal polymer is nematic aligned, and the angle between the director of the liquid crystal polymer and the film plane at this time is different between the upper surface and the lower surface of the film. Therefore, since the angle formed by the director and the film plane is different between the vicinity of the upper surface interface and the vicinity of the lower surface interface, the angle continuously changes between the upper surface and the lower surface of the film. I can say that.
[0011]
Further, in the viewing angle improving film of the present invention having the nematic hybrid alignment form, the director of the liquid crystalline polymer is oriented at different angles at all positions in the film thickness direction. Therefore, when viewed as a film structure, the optical axis no longer exists.
The film as described above can be obtained by using, as a film material, a liquid crystalline composition containing at least a liquid crystalline polymer (a) exhibiting optically positive uniaxial properties and a specific compound (b) described later.
[0012]
Examples of the liquid crystalline polymer include condensed liquid crystalline polymers obtained by condensing a compound having a carboxylic acid group, an alcohol group, a phenol group, an amino group, a thiol group, an acryloyl group, a methacryloyl group, a vinyl group, and an allyl group. Liquid crystalline vinyl polymers obtained from liquid crystalline compounds having a double bond, etc., liquid crystalline polysiloxanes synthesized from liquid crystalline compounds having alkoxysilane groups, liquid crystalline compounds synthesized from liquid crystalline compounds having epoxy groups, etc. Examples thereof include a mixture of an epoxy resin and the liquid crystalline polymer. Among the liquid crystalline polymers, condensed liquid crystalline polymers are most preferable from the viewpoint of the optical properties of the obtained film.
[0013]
The condensed liquid crystalline polymer can be usually obtained by condensing a bifunctional monomer by an appropriate method. As the bifunctional monomer, a bifunctional monomer having an aromatic or cyclohexane ring is desirable. Specifically, diamines such as phenylenediamine, hydroquinone, 2-methylhydroquinone, resorcinol, catechol, 4-methylcatechol, 4 Diols such as -tert-butylcatechol and 2,3-dihydroxynaphthalene, dithiols such as 1,4-phenylenedithiol and 1,2-phenylenedithiol, salicylic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 3 -Hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, hydroxycarboxylic acids such as 7-hydroxy-2-naphthoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, etc. Amino acids, phthalic acid, isof Phosphoric acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 4,4′-stilbene dicarboxylic acid, 1, Examples thereof include dicarboxylic acids such as 4-cyclohexanedicarboxylic acid. Among these, a condensed liquid crystalline polymer containing a catechol unit as an essential structural unit as a component having a hydroxy group is most preferably used.
[0014]
In addition, for example, oxalic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and other aliphatic dicarboxylic acids, ethylene glycol, propylene glycol, butane, etc. Diol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol and other aliphatic diols, diaminoethane, diaminopropane, diaminobutane, diaminopentane, diaminohexane, diaminoheptane, diaminooctane, diaminononane, diaminodecane Such as aliphatic diamine, hydroxyacetic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxyhexanoic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, Dorokishinonan acid, condensed type liquid crystalline polymer obtained by the like aliphatic hydroxycarboxylic acids added in the raw material monomer such as hydroxy decanoic acid can also be used.
[0015]
Further, if necessary, a monofunctional monomer can be added to the raw material monomer in order to modify the main chain terminal of the liquid crystalline polymer. Specific examples of the monofunctional monomer include monomers having one carboxylic acid group, amine group, alcohol group, phenol group, thiol group and the like in one molecule.
Examples of the monofunctional monomer having a carboxylic acid group include aromatic carboxylic acids and aliphatic carboxylic acids.
[0016]
Aromatic carboxylic acids include benzoic acids substituted at the 2-position, 3-position or 4-position with an alkyl group or alkoxy group having 1 to 20 carbon atoms, such as methoxybenzoic acid, ethoxybenzoic acid, propoxybenzoic acid. Acid, butoxybenzoic acid, pentoxybenzoic acid, hexyloxybenzoic acid, heptyloxybenzoic acid, octyloxybenzoic acid, nonyloxybenzoic acid, decyloxybenzoic acid, toluic acid, ethylbenzoic acid, propylbenzoic acid, butylbenzoic acid, pentylbenzoic acid, hexyl Preferred examples include benzoic acid, heptyl benzoic acid, octyl benzoic acid, nonyl benzoic acid, decyl benzoic acid and the like.
[0017]
On the other hand, examples of the aliphatic carboxylic acid include aliphatic carboxylic acids having 2 to 20 carbon atoms, specifically, acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, etc. it can.
Among the above monofunctional monomers, 4-methoxybenzoic acid, 4-ethoxybenzoic acid, 4-propoxybenzoic acid, 4-butoxybenzoic acid, 4-pentoxybenzoic acid, 4-hexyloxybenzoic acid substituted at the 4-position , 4-heptyloxybenzoic acid, 4-octyloxybenzoic acid, 4-nonyloxybenzoic acid, 4-decyloxybenzoic acid and the like can be mentioned as suitable ones.
[0018]
Examples of the monofunctional monomer having an amine group include aromatic amines and aliphatic amines.
Examples of the aromatic amines include anilines substituted at the 2-position, 3-position or 4-position with an alkyl group or alkoxy group having 1 to 20 carbon atoms. Examples of the aliphatic amines include aliphatic amines having 2 to 20 carbon atoms.
[0019]
When using the monofunctional monomer as described above, it is also possible to use a monofunctional monomer having an optically active group if necessary. Specific examples include benzoic acid derivatives in which a part of the aromatic ring is substituted with an optically active group, optically active aliphatic acids, and the like. Among these, 4-methylpropoxybenzoic acid, 4- ( 2-methylbutoxy) benzoic acid, 4-methylbutoxybenzoic acid, 4-methylpentyloxybenzoic acid, 4-methylhexyloxybenzoic acid, 4-methylheptyloxybenzoic acid, 4-menthyloxybenzoic acid, 4-isomenthyloxybenzoic acid A benzoic acid compound in which a part of the aromatic ring is substituted with an optically active group such as an acid or 4-bornyloxybenzoic acid is preferably used.
[0020]
Examples of the monofunctional monomer having an alcohol group or a phenol group include phenols and aliphatic alcohols. Examples of the phenols include phenols substituted at the 2-position, 3-position or 4-position with an alkyl group having 1 to 20 carbon atoms, an alkoxy group or an alkoxycarbonyloxy group. Examples of aliphatic alcohols include aliphatic alcohols having 2 to 20 carbon atoms. Specific examples of the phenols and aliphatic alcohols include cresol, ethylphenol, nonylphenol, butanol, pentanol, hexanol, and cyclohexanol. Cresol and nonylphenol are preferably used.
[0021]
The alkyl group, alkoxy group, and aliphatic group described above may contain an unsaturated bond, and may further have an optically active group. Further, if necessary, as a monomer having three or more functional groups, trimellitic acid, dihydroxybenzoic acid, hydroxybenzenedicarboxylic acid, benzenetricarboxylic acid, pyromellitic acid, or the like, 1-methylethanediol, 1 -Ethylethanediol, 1-methylpropanediol, 1-methylbutanediol, 2-methylbutanediol, 1-methylpentanediol, 2-methylpentanediol, cyclopentanediol, cyclohexanediol, 2-methylsuccinic acid, 3-methyl Adipic acid or the like can also be used.
[0022]
A method for condensing these monomers to obtain a condensed liquid crystalline polymer, specifically, a liquid crystalline polyester is not particularly limited, and any method known in the art can be appropriately employed. For example, a method in which carboxylic acid is activated by making carboxylic acid an acid halide or dicyclohexylcarbodiimide or the like is present and then reacted with alcohol, amine, etc., phenol is acetated, and then reacted with carboxylic acid to remove acetic acid And a method of synthesizing by a dealcoholization reaction by reacting with an alcohol in the presence of an appropriate catalyst, if necessary, after converting the carboxylic acid to an esterified product such as methyl ester.
[0023]
When the condensed liquid crystalline polymer as described above is used in the present invention, a mixture of two or three or more condensed liquid crystalline polymers can be used, and as long as the effects of the present invention are not impaired. Non-liquid crystalline polymers, liquid crystalline vinyl polymers, liquid crystalline polysiloxanes, liquid crystalline epoxy resins, and the like can also be mixed.
The liquid crystalline polymer desirably has tilt alignment or homeotropic alignment in the liquid crystal state. Here, the tilt alignment is an acute angle side formed by the director of the liquid crystalline polymer in the vicinity of the substrate and the film plane when the liquid crystalline polymer is heat-treated on a suitable substrate with air or vacuum on the upper surface. It means a property that can take a state where the angle near the interface on the air or vacuum side is larger than the angle. On the other hand, homeotropic orientation refers to the property that the director of the liquid crystalline polymer can be in an orientation state substantially perpendicular to the substrate plane in the same case.
[0024]
Whether or not the liquid crystalline polymer has tilt alignment or homeotropic alignment is determined by forming a liquid crystalline polymer layer on the substrate and determining the alignment state. The substrate that can be used for this determination is not particularly limited. For example, a glass substrate (specifically, optical glass such as soda glass, potassium glass, borosilicate glass, crown glass, or flint glass), a liquid crystalline polymer, and the like can be used. For example, polyethylene terephthalate, polyethylene naphthalate, polyphenylene oxide, polyimide, polyamideimide, polyetherimide, polyamide, polyetherketone, polyetheretherketone, polyketonesulfide, polyethersulfone, etc. that have heat resistance in the temperature range exhibiting a liquid crystal state. The representative plastic film and sheet can be mentioned.
[0025]
The substrate exemplified above is used after the surface is cleaned with acid, alcohol, detergent or the like. Further, the determination of the orientation is preferably performed on a substrate that has not been subjected to a surface treatment such as silicon treatment, rubbing treatment, or uniaxial stretching treatment. However, the rubbing treatment or uniaxial stretching treatment was performed to determine the tilt orientation. A substrate can also be used.
[0026]
An optically positive uniaxial liquid crystalline polymer used in the present invention forms a liquid crystalline polymer film having a thickness of 0.1 μm to 1000 μm on the substrate, and the liquid crystalline polymer exhibits a liquid crystal state. When heat treatment is performed at the indicated temperature, it is desirable that the film be tilted or homeotropically aligned on at least one of these exemplified substrates. However, some liquid crystalline polymers are specifically homeotropically aligned at a temperature near the liquid crystal-isotropic phase transition point. Therefore, it is usually desirable to perform the heat treatment as described above at a temperature of 15 ° C. or less, preferably 20 ° C. or less from the liquid crystal-isotropic phase transition point. At this time, if the liquid crystalline polymer exhibits tilt orientation, the state where the extinction axes of adjacent domains are the same and the disclination line is inserted (tilt direction to be described later) is observed under a polarizing microscope. Can be found. In addition, as long as it exhibits homeotropic orientation, the orientation can be confirmed with a conoscope or the like.
[0027]
The molecular weight of the liquid crystalline polymer used in the present invention is usually 0.01 to 1 in logarithmic viscosity measured at 30 ° C. in various solvents such as a mixed solvent of phenol / tetrachloroethane (60/40 (weight ratio)). 0.0, preferably 0.03 to 0.5, more preferably 0.05 to 0.3. When the logarithmic viscosity is less than 0.01, the mechanical strength of the film may be reduced, or the reliability with respect to high temperature and high humidity may be impaired. On the other hand, when the ratio is larger than 1.0, the alignment may be hindered, or the viscosity at the time of liquid crystal formation may be too high, and the time required for the alignment may be increased.
[0028]
In the present invention, the number of main chain atoms in which a plurality of alicyclic rings and / or aromatic rings are bonded to different ring carbon atoms in the above-described liquid crystalline polymer (a) exhibiting positive uniaxiality. The molecular weight is 1000 or less, which are linked through 0 to 4 linked chains, and each terminal ring is bonded with a hydrocarbon group having 1 to 20 carbon atoms via a linked chain having 0 to 4 main chain atoms. The liquid crystalline composition to which the polycyclic compound (b) is added is provided.
[0029]
The polycyclic compound (b) used in the present invention has the above-mentioned chemical structural characteristics, and can be expressed as follows when expressed as a general formula:
R¹-(B¹-A¹)-(B²-A²) -...- (Bⁿ-Aⁿ-B^{n + 1}-R²
(Wherein R¹, R²Are each a hydrocarbon group having 1 to 20 carbon atoms, and A¹~ AⁿIs a ring structure but two adjacent BⁿAre ring structures bonded to different atoms constituting the ring structure, and B¹~ B^{n + 1}Is a single bond or adjacent R¹, R²Or AⁿIt is an organic group having 1 to 4 atoms in between, and n is an integer of 2 to 8. )
[0030]
Where A¹~ AⁿIs two adjacent BⁿThe ring structure is bonded to each other atom constituting the ring structure. In particular, the present invention preferably has at least one 6-membered ring structure as the ring structure. Here, the ring structure is expressed as an alicyclic ring and / or an aromatic ring. Specifically, in addition to a benzene group, an indene group, etc., a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, Polycyclic aromatic groups such as pyrene group and perylene group, heteroaromatic groups such as pyridine group, pyrimidine group, pyrazine group, pyridazine group and triazole group, and polycyclic aromatic groups containing heteroatoms such as isoquinoline group and quinoline group Can be. These aromatic groups may be linked by a plurality of non-aromatic cyclic structures such as fluorene group, acenaphthylene group, dibenzofuran group, carbazole group, xanthene group, phenoxazine group, phenazine group, dibenzodioxin group, etc. There can also be. In addition, a ring structure in which some or all of the unsaturated bonds in the ring structure are hydrogenated may be used. Specifically, a cyclohexane group, a cyclohexene group, a tetrahydroxynaphthalene group, a decahydroxynaphthalene group, an acenaphthene group, or the like may be used. Can be mentioned. If necessary, the ring structure may have one or more substituents. Examples of the substituent include a hydrocarbon group having 1 to 10 carbon atoms or an alkoxy group, a phenoxy group, a trifluoromethyl group, a hydroxy group, an amino group, a nitro group, and a halogen atom. When a plurality of substituents are present, the substituents may be the same or different.
[0031]
B in the general formula (1)¹~ B^{n + 1}Are each a single bond or an adjacent R¹, R²Or AⁿAn organic group having 1 to 4 atoms interposed therebetween does not form part of the ring structure. Specifically as an organic group,
-O-, -NR₁-,-(C = O)-, -O- (C = O)-,
-NR- (C = O)-, -CR₁= CR₁-, -C≡C-,
-CR₂-CR₁= CR₁-CR₂-, -CR₂-C≡C-CR₂−,
-O- (C = O) -C≡C-,-(S = O)-,
-NR₁-(C = O) -CR₁= CR₁-, -O-CR₁= CR₁-O-,
-O- (C = O) -C = C-,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1-2),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-NR- (CR₂)_n-(N = 1 to 3),
-N = CH- (CR₂)_n-(N = 0-2),
-(CR₂)_n-O- (CO)-(n = 1-2)
Etc. can be illustrated. Where R₁, R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂If there are n, they may be different from each other.
[0032]
Especially as the organic group,
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁-,-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (CO)-(n = 1-2),
Etc. are suitable.
[0033]
Further, R in the general formula (1)¹And R²Are hydrocarbon groups having 1 to 20 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group. Group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, etc., linear saturated hydrocarbon group, methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1-methylhexyl group 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1- Tilheptyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 6-methylheptyl group, 1-methyloctyl group, 1-methylnonyl group, 2-methylhexyl group, Branches such as 3,7-dimethyloctyl group, 3,5,5-trimethylhexyl group, dimethylethyl group, secondary or tertiary saturated hydrocarbon group, allyl group, butenyl group, pentenyl group, hexenyl group, etc. Unsaturated hydrocarbon group, cyclopentyl group, cyclohexyl group, cyclohexenyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylpropyl group, phenyl group, benzyl group, phenethyl group, naphthyl group, naphthylmethyl group, menthyl group, norbornyl group, Hydrocarbons with a cyclic structure such as bornyl and isomenthyl groups The like may be exemplified.
Here, a more specific structural formula of the general formula (1) is exemplified below.
[0034]
[Chemical 1]

[0035]
In Structural Formula 1, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R^TenIs a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁Is at least one organic group selected from a single bond or group A, and X₂, X_ThreeIs an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂And X_ThreeIn the organic group, a structural formula in which the bond is reversed left and right is also included.
[0036]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0037]
[Chemical formula 2]

[0038]
In Structural Formula 2, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R¹⁴Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂Is at least one organic group selected from a single bond or group A, and X_Three, X_FourIs an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂, X_ThreeAnd X_FourIn the organic group, a structural formula in which the bond is reversed left and right is also included.
[0039]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0040]
[Chemical 3]

[0041]
In Structural Formula 3, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R¹⁸Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂Is at least one organic group selected from a single bond or group A, and X_Three, X_FourIs an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂, X_ThreeAnd X_FourIn the organic group, a structural formula in which the bond is reversed left and right is also included.
[0042]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0043]
[Formula 4]

[0044]
In Structural Formula 4, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R¹⁴Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂Is at least one organic group selected from a single bond or group A, and X_Three, X_FourIs an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂, X_ThreeAnd X_FourIn the organic group, a structural formula in which the bond is reversed left and right is also included.
[0045]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0046]
[Chemical formula 5]

[0047]
In Structural Formula 5, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R¹⁴Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂Is at least one organic group selected from a single bond or group A, and X_Three, X_FourIs an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂, X_ThreeAnd X_FourIn the organic group, a structural formula in which the bond is reversed left and right is also included.
[0048]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0049]
[Chemical 6]

[0050]
In Structural Formula 6, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R¹⁸Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂Is at least one organic group selected from a single bond or group A, and X_Three, X_FourIs an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂, X_ThreeAnd X_FourIn the organic group, a structural formula in which the bond is reversed left and right is also included.
[0051]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0052]
[Chemical 7]

[0053]
In Structural Formula 7, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R¹⁸Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂, X_ThreeIs at least one organic group selected from a single bond or group A, and X_Four, X_FiveIs an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂, X_Three, X_FourAnd X_FiveIn the organic group, a structural formula in which the bond is reversed left and right is also included.
[0054]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0055]
[Chemical 8]

[0056]
In Structural Formula 8, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R^{twenty two}Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂, X_Three, X_FourIs at least one organic group selected from a single bond or group A, and X_Five, X₆Is an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂, X_Three, X_Four, X_FiveAnd X₆In the organic group, a structural formula in which the bond is reversed left and right is also included.
[0057]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0058]
[Chemical 9]

[0059]
In Structural Formula 9, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R⁶Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂Is an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁And X₂In the organic group, a structural formula in which the bond is reversed left and right is also included.
[0060]
[Chemical Formula 10]

[0061]
In Structural Formula 10, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R⁶Is a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂Is an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁And X₂In the organic group, a structural formula in which the bond is reversed left and right is also included.
[0062]
Embedded image

[0063]
In Structural Formula 11, R¹, R²Is a hydrocarbon group having 1 to 20 carbon atoms, R^Three~ R^TenIs a hydrogen atom, F, Cl, Br, a hydrocarbon group having 1 to 6 carbon atoms or an alkoxy group, X₁, X₂Is at least one organic group selected from a single bond or group A, and X_Three, X_FourIs an organic group selected from a single bond, —O—, and —O— (C═O) —. Where X₁, X₂, X_ThreeAnd X_FourIn the organic group, a structural formula in which the bond is reversed left and right is also included.
[0064]
Group A
-O-,-(C = O)-, -O- (C = O)-, -NR₁-(C = O)-,
-CR₁= CR₁-, -NR₁-(C = O) -CR₁= CR₁−,
-O- (C = O) -CR₁= CR₁−,
-(CR₂)_n-(N = 1 to 4),
-O- (CR₂)_n-O- (n = 1 to 4),
-(CR₂)_n-O-CH₂-(N = 1, 2),
-O- (CR₂)_n-(N = 1 to 3),
-O- (C = O)-(CR₂)_n-(N = 1-2),
-(CR₂)_n-O- (C = O)-(n = 1-2),
(In group A, R₁And R₂Represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. Also R₁Need not be identical to each other and R₂When there are n, each may be different. )
[0065]
There is no restriction | limiting in particular about the synthesis | combining method of the said compound which has the above structures, Any method well-known in the said field | area is employable. Further, the compound need not be a pure water compound, and as long as it does not interfere with the production or use of the film of the present invention, such as reducing orientation or coloring, for example, removing impurities by-produced during synthesis. It can also be used without. Furthermore, it can also be used as a mixture of plural types of the compounds.
[0066]
The compound represented by the general formula (1) is added in an amount of 0.1 wt% to 20 wt%, preferably 0.3 wt% to 10 wt%, with respect to the liquid crystalline polymer described above. When the addition amount is less than 0.1% by weight, there is a possibility that a uniform alignment form cannot be obtained. On the other hand, if it is more than 20% by weight, adverse effects such as heat resistance may appear in reliability tests.
[0067]
In the present invention, a liquid crystalline composition containing at least the liquid crystalline polymer exhibiting optically positive uniaxial properties and the compound represented by the general formula (1) as described above is uniformly in a liquid crystal state on an alignment substrate. The film for an optical element is produced by preferably aligning nematic hybrid alignment and then fixing the alignment form. For that purpose, it is desirable to follow the alignment substrate and each process described below.
[0068]
First, the alignment substrate will be described.
In general, in order to obtain nematic hybrid alignment using a liquid crystalline composition, it is desirable to sandwich the upper and lower sides of the liquid crystalline composition layer at different interfaces, and when the upper and lower sides are sandwiched at the same interface, the liquid crystalline composition The orientation at the upper and lower interfaces of the layers becomes the same, making it difficult to obtain a nematic hybrid orientation.
[0069]
In producing the film for optical elements of the present invention, as a specific embodiment, a single alignment substrate and an air interface are used, the lower interface of the liquid crystal composition layer is used as the alignment substrate, and the liquid crystal composition is used. The top interface of the layer is in contact with air. Although it is possible to use alignment substrates having different interfaces up and down, it is preferable to use a single alignment substrate and an air interface in the manufacturing process.
[0070]
The alignment substrate that can be used in the present invention desirably has anisotropy so that the direction in which the liquid crystal molecules tilt (projection of the director onto the alignment substrate) can be defined. If the alignment substrate cannot completely define the direction in which the liquid crystal is tilted, only an alignment form tilted in a disordered direction can be obtained (the vector in which the director is projected onto the substrate becomes disordered).
[0071]
Specific examples of the alignment substrate that can be used in the present invention include polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyetherketone, polyketonesulfide, polyethersulfone, polysulfone, polyphenylenesulfide, and polyphenylene. Plastic film substrates such as oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, cellulosic plastics, epoxy resin, phenol resin, and uniaxially stretched plastic film substrate, Aluminum, iron, copper and other metal substrates with slits on the surface, slits on the surface Etching alkaline glass, borosilicate glass, a glass substrate such as flint glass, and the like.
[0072]
In the present invention, a rubbing plastic film substrate obtained by rubbing the plastic film substrate or a plastic thin film subjected to rubbing treatment, for example, various substrates having a rubbing polyimide film, a rubbing polyvinyl alcohol film, and the like, and oblique deposition of silicon oxide The above various substrates having a film or the like can also be used.
[0073]
As the substrate suitable for forming the liquid crystalline composition of the present invention in a nematic hybrid alignment in the above various alignment substrates, various substrates having a rubbing polyimide film, a rubbing polyimide substrate, a rubbing polyetheretherketone substrate, a rubbing poly Examples include an ether ketone substrate, a rubbing polyether sulfone substrate, a rubbing polyphenylene sulfide substrate, a rubbing polyethylene terephthalate substrate, a rubbing polyethylene naphthalate substrate, a rubbing polyarylate substrate, and a cellulosic plastic substrate.
[0074]
In the film for optical elements of the present invention, when the liquid crystalline composition forms a nematic hybrid alignment, the angle formed by the director of the liquid crystalline composition and the film plane differs between the upper surface and the lower surface of the film. The film surface on the substrate side can be adjusted to an angle range of 0 ° or more and 20 ° or less or 30 ° or more and 90 ° or less depending on the alignment treatment method and the type of liquid crystal composition. In general, it is desirable in terms of the manufacturing process to adjust the angle formed by the director of the liquid crystalline composition in the vicinity of the film interface in contact with the alignment substrate and the film plane to an angle range of 0 ° to 20 °. In this case, the angle formed by the director and the film plane in the vicinity of the film interface on the side not in contact with the alignment substrate is adjusted to an angle range of 30 degrees or more and 90 degrees or less.
[0075]
The film for an optical element of the present invention can be obtained by uniformly applying a liquid crystalline composition on the alignment substrate as described above, and then performing a uniform alignment process and an alignment form fixing process. Application of the liquid crystalline composition to the alignment substrate can be usually performed in a solution state in which the liquid crystalline composition is dissolved in various solvents or in a molten state in which the liquid crystalline composition is melted. In the manufacturing process, solution coating, in which a liquid crystal composition is dissolved in a solvent, is preferably applied.
In solution application, first, the liquid crystalline composition is dissolved in a solvent to prepare a solution having a predetermined concentration. Here, the film thickness (thickness of the layer formed from the liquid crystalline polymer composition) is determined at the stage of applying the liquid crystalline composition to the substrate. Need to control.
[0076]
The above solvent cannot be generally specified depending on the type of liquid crystal composition (composition ratio, etc.), but usually halogenated chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, orthodichlorobenzene, etc. Hydrocarbons, phenols such as phenol and parachlorophenol, aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene and 1,2-dimethoxybenzene, acetone, ethyl acetate, tert-butyl alcohol, glycerin, Ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, ethyl cellosolve, butyl cellosolve, 2-pyrrolidone, N-methyl-2- Pyrrolidone, pyridine, triethylamine, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, acetonitrile, butyronitrile, carbon disulfide, and solvent mixtures thereof, for example, mixed solvents of halogenated hydrocarbons and phenols are used.
[0077]
The concentration of the solution depends on the solubility of the liquid crystal composition to be used and the film thickness of the final optical element film, but cannot be generally stated, but is usually used in the range of 3 to 50% by weight, Preferably it is the range of 5-30 weight%.
Further, when a solvent having a high surface tension is used, a surfactant can be added to the solution if necessary for stable application. As the surfactant that can be used, any surfactant can be used as long as it can lower the surface tension of the solution and stabilize the coating film, but a fluorosurfactant is particularly preferably used. As the surfactant, commercially available ones can be used as appropriate. For example, Florard (manufactured by 3M), Paintad (manufactured by Dow Corning), Surflon (manufactured by Asahi Glass), Unidyne (manufactured by Daikin Industries) , Mega Fuck (Dainippon Ink Co., Ltd.), F Top (Shin-Akita Kasei Co., Ltd.), Footage (Neos Co., Ltd.), Aron-G (Toagosei Co., Ltd.), Modiper (Nippon Yushi Co., Ltd.), etc. . In addition, this invention is not limited to these, For example, it cannot be overemphasized that the products of other companies which have an equivalent chemical structure can also be used, for example.
[0078]
The amount of the surfactant used is usually in the range of 0.001 g to 1 g with respect to 1 kg of the solution. If the amount used is more than 1 g, it becomes a foreign substance in the liquid crystal composition and may cause defects. In addition, it takes a long time to form the alignment and may cause an adverse effect on the alignment mode of the liquid crystal such as causing an alignment inhibition.
The liquid crystalline composition solution adjusted to a desired concentration using the above solvent is applied on the alignment substrate described above. As a coating method, a spin coating method, a roll coating method, a die coating method, a printing method, a dipping method, a curtain coating method, or the like can be adopted.
[0079]
After coating, the solvent is removed, and a layer of a liquid crystalline composition having a uniform film thickness is formed on the alignment substrate. Solvent removal conditions are not particularly limited, as long as the solvent can be removed generally and the layer of the liquid crystalline composition does not flow or even flows down. Usually, the solvent is removed by drying at room temperature, drying in a drying furnace, blowing warm air or hot air, and the like.
The stage of this coating / drying process is to first form a liquid crystalline composition layer uniformly on the substrate, and the liquid crystalline composition has not yet formed liquid crystal alignment. The next heat treatment step completes a monodomain liquid crystal alignment, preferably a nematic hybrid alignment.
[0080]
In forming the nematic hybrid alignment by heat treatment, the viscosity of the liquid crystalline composition is preferably low in the sense of assisting the alignment due to the interfacial effect, and therefore the heat treatment temperature is preferably high. Depending on the liquid crystalline composition, the average tilt angle described later may vary depending on the heat treatment temperature. In that case, it is necessary to set the heat treatment temperature in order to obtain an average tilt angle according to the purpose. For example, when it is necessary to perform heat treatment at a relatively low temperature in order to obtain an alignment having a certain tilt angle, the liquid crystalline composition has a high viscosity at a low temperature, and the time required for the alignment becomes long. In such a case, it is effective to perform a heat treatment at a high temperature once to obtain a monodomain orientation, and then gradually or gradually lower the heat treatment temperature to the target temperature. In any case, it is desirable to perform heat treatment at a temperature higher than the glass transition point in accordance with the characteristics of the liquid crystalline composition to be used, specifically the liquid crystalline polymer. Further, when two or more kinds of compositions are used as the liquid crystalline polymer as the liquid crystalline composition of the present invention, it is desirable to set the heat treatment temperature according to the glass transition point of the liquid crystalline polymer. Specifically, it is preferable to perform heat treatment at a temperature higher than the glass transition point of the liquid crystalline polymer compound having the highest glass transition point among the two or more types of liquid crystalline polymer compounds constituting the liquid crystalline polymer. .
[0081]
The heat treatment temperature required for forming the liquid crystal alignment is usually in the range of 50 to 300 ° C, preferably 70 to 280 ° C, more preferably 100 to 260 ° C. Further, as described above, it is also possible in the present invention to perform heat treatment continuously at a plurality of temperatures, that is, heat treatment at a certain temperature and then heat treatment at a temperature lower or higher than that temperature.
In addition, the heat treatment time necessary for the liquid crystal composition to be sufficiently aligned on the alignment substrate varies depending on the type of liquid crystal composition used (for example, composition ratio) and the heat treatment temperature. The range is usually 10 seconds to 120 minutes, preferably 30 seconds to 60 minutes. If it is shorter than 10 seconds, the orientation may be insufficient. Moreover, when longer than 120 minutes, productivity may fall and it is not desirable.
[0082]
In this way, a uniform nematic hybrid alignment can be obtained over the entire surface of the alignment substrate in the liquid crystal state.
In the present invention, a magnetic field or an electric field may be used in the heat treatment step. However, when a too strong magnetic field or electric field is applied while heat treatment, a uniform field force acts on the liquid crystalline composition during the application, so that the director of the liquid crystal is easily oriented in a certain direction. That is, it is difficult to obtain a nematic hybrid orientation in which the director forms an angle different depending on the film thickness direction as in the present invention.
[0083]
The nematic hybrid alignment thus formed in the liquid crystal state of the liquid crystalline composition is then fixed to the liquid crystalline composition by cooling to a temperature below the liquid crystal transition point of the liquid crystalline composition without impairing the uniformity of the alignment. Can do. In general, when a liquid crystalline composition having a smectic phase or a crystalline phase at a lower temperature than the nematic phase is used, the nematic orientation in the liquid crystal state may be broken by cooling. In the present invention,
(1) No smectic phase or crystalline phase at a temperature below the temperature range showing a nematic phase,
(2) Even if it has a crystal phase or smectic phase, it has the property that no smectic phase or crystal phase appears during cooling.
And
(3) There is no fluidity in the operating temperature range of the optical element film, and the orientation form does not change even when an external field or external force is applied.
The liquid crystal composition having such properties as described above can be used to fix a completely monodomain liquid crystal alignment, preferably a nematic hybrid alignment, without destroying the alignment form due to a phase transition to a smectic phase or a crystal phase. .
[0084]
The cooling temperature is not particularly limited as long as it is a temperature below the liquid crystal transition point. For example, uniform liquid crystal alignment can be fixed by cooling at a temperature 10 ° C. lower than the liquid crystal transition point. The cooling means is not particularly limited, and can be fixed simply by taking it out from the heating atmosphere in the heat treatment step to an atmosphere below the liquid crystal transition point, for example, at room temperature. In order to increase production efficiency, forced cooling such as air cooling and water cooling, and heat removal may be performed. However, depending on the liquid crystalline composition, the average tilt angle obtained under the influence of the cooling rate may be slightly different. When such a liquid crystalline composition is used and it becomes necessary to strictly control the average tilt angle, it is desirable that the cooling operation is appropriately performed in consideration of the cooling conditions.
[0085]
Next, the angle control in the film thickness direction of nematic hybrid orientation in the present invention will be described. In the optical element film of the present invention, when the nematic hybrid alignment is fixed, the absolute value of the angle formed by the director of the liquid crystalline composition in the vicinity of the film interface and the film plane is on one of the upper surface and the lower surface of the film. Is in the range of 0 ° to 20 °, and in the range opposite to the surface is in the range of 30 ° to 90 °. By appropriately selecting the type and composition ratio of the liquid crystalline composition to be used, the alignment substrate, the heat treatment conditions, and the like, the desired angle can be controlled. Even after the nematic hybrid orientation is fixed, it is possible to control the angle to a desired angle by using a method such as uniformly shaving the film surface or immersing in a solvent to uniformly melt the film surface. In addition, it is necessary to select suitably the solvent used in this case according to the kind and composition ratio of a liquid crystalline composition, and the kind of alignment substrate.
[0086]
The film for optical elements of the present invention obtained by the above steps can be obtained by uniformly aligning and fixing an alignment form called nematic hybrid alignment. Further, since the orientation is formed, the upper and lower sides of the film are not equivalent, and there is anisotropy in the in-plane direction. Therefore, by utilizing the film as a viewing angle improving film for a liquid crystal display element and arranging the film on an LCD, various characteristics can be extracted.
[0087]
The method for using the optical element film of the present invention as a viewing angle improving film will be described in more detail below.
When placing a viewing angle improving film in a twisted nematic liquid crystal cell,
(1) The above-mentioned oriented substrate is peeled from the film and used as a viewing angle improving film alone.
(2) Used as it is formed on the alignment substrate,
(3) A viewing angle improving film is laminated on another substrate different from the oriented substrate.
It is possible.
[0088]
When used as a single film, a method of mechanically peeling the alignment substrate at the interface with the viewing angle improving film using a roll, a method of mechanically peeling after dipping in a poor solvent for all structural materials, A method of peeling by applying ultrasonic waves in a poor solvent, a method of peeling by applying a temperature change using the difference in thermal expansion coefficient between the alignment substrate and the film, dissolving the alignment substrate itself or the alignment film on the alignment substrate A single film can be obtained by a removal method or the like. The peelability varies depending on the type of liquid crystal composition used and the adhesion between the alignment substrate and the method most suitable for the system should be adopted. When the viewing angle improving film is used alone, depending on the film thickness, it may not have a self-supporting property. In that case, a substrate preferable in terms of optical properties, such as polymethacrylate, polycarbonate, polyvinyl alcohol, polyether sulfone, polysulfone. It is desirable to use it by fixing it on a plastic substrate such as polyarylate, polyimide, amorphous polyolefin, or triacetyl cellulose via an adhesive or a pressure-sensitive adhesive because of the strength and reliability of the film.
[0089]
Next, the case where a viewing angle improvement film is used in the state formed on the alignment substrate is demonstrated. When the alignment substrate is transparent and optically isotropic, or when the alignment substrate is a necessary member for the TN-LCD, the alignment substrate can be incorporated into the TN-LCD as it is.
[0090]
Further, the case where the viewing angle improving film of the present invention obtained by aligning and fixing the liquid crystalline composition on the alignment substrate is peeled off from the substrate and laminated on another substrate suitable for optical use will be described. . That is, the viewing angle improving film of the present invention can be incorporated in a TN-LCD as a compensation element, which is a laminate composed of at least another substrate different from the alignment substrate. For example, when the alignment substrate to be used is necessary for obtaining nematic hybrid alignment, but the substrate has an unfavorable influence on TN-LCD, the viewing angle after the substrate is fixed to alignment is used. It can be used by removing from the improved film. Specifically, the following method can be employed.
[0091]
A substrate (hereinafter referred to as a second substrate) suitable for a liquid crystal display element incorporated in a target TN-LCD and a viewing angle improving film on an alignment substrate are attached using, for example, an adhesive or a pressure-sensitive adhesive. Next, the alignment substrate can be peeled off at the interface with the viewing angle improving film, and the film can be transferred to a second substrate side suitable for a liquid crystal display device to obtain a compensation element.
[0092]
The second substrate used for transfer is not particularly limited as long as it has an appropriate flatness, but a glass substrate or a transparent plastic film having optical isotropy is preferably used. Examples of such plastic films include polymethyl methacrylate, polystyrene, polycarbonate, polyether sulfone, polyphenylene sulfide, polyarylate, amorphous polyolefin, triacetyl cellulose, and epoxy resin. Of these, polymethyl methacrylate, polycarbonate, polyarylate, polyether sulfone, triacetyl cellulose and the like are preferably used. Moreover, even if it is optically anisotropic, an optically anisotropic film or the like can also be used if it is a necessary member for the TN-LCD. Examples of the optically anisotropic film include a retardation film and a polarizing film obtained by stretching a plastic film such as polycarbonate or polystyrene.
[0093]
Furthermore, the liquid crystal cell itself can be mentioned as an example of the 2nd board | substrate used. The liquid crystal cell uses two upper and lower electrode-attached glass or plastic substrates. If the viewing angle improving film of the present invention is transferred onto either the upper or lower glass or plastic substrate, the film can be incorporated. It has already been achieved. It is of course possible to manufacture the viewing angle improving film of the present invention using the glass or plastic substrate itself forming the liquid crystal cell as the alignment substrate.
The 2nd board | substrate demonstrated above does not need to have the orientation control ability of a liquid crystalline composition substantially. Further, an alignment film or the like is not required between the second substrate and the film.
[0094]
The adhesive or pressure-sensitive adhesive for adhering the second substrate used for transfer and the viewing angle improving film of the present invention is not particularly limited as long as it is an optical grade, but is acrylic, epoxy, ethylene-acetic acid. A vinyl copolymer system, a rubber system, a urethane system, and a mixed system thereof can be used. As the adhesive, any adhesive such as a thermosetting type, a photocurable type, and an electron beam curable type can be used without any problem as long as it has optical isotropy.
[0095]
The viewing angle improving film of the present invention can be transferred to a second substrate suitable for a liquid crystal display element by peeling the alignment substrate at the interface with the film after bonding. The method of peeling was explained above, but mechanical peeling using a roll, etc., method of mechanical peeling after dipping in a poor solvent for all structural materials, peeling by applying ultrasonic waves in the poor solvent And a method of peeling by applying a temperature change using a difference in thermal expansion coefficient between the alignment substrate and the film, a method of dissolving and removing the alignment substrate itself or the alignment film on the alignment substrate, and the like. . The peelability varies depending on the type of liquid crystal composition used and the adhesion between the alignment substrate and the method most suitable for the system should be adopted.
The viewing angle improving film of the present invention can be provided with a protective layer such as a transparent plastic film for the purpose of surface protection, strength increase, and environmental reliability improvement.
[0096]
The viewing angle improving film thus obtained has a particularly excellent viewing angle compensation effect for TN-LCD. The film thickness for the film of the present invention to develop a more suitable compensation effect for various TN-LCDs depends on the type of TN-LCD and various optical parameters, so that Although it cannot be said, it is usually 0.1 μm or more and 20 μm or less, preferably 0.2 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 5 μm or less. When the film thickness is less than 0.1 μm, a sufficient compensation effect may not be obtained. Further, if the film thickness exceeds 20 μm, the display may be unnecessarily colored.
However, in order to bring out the performance of the viewing angle improving film of the present invention to a higher level, it is desirable to consider the optical parameters and axial arrangement of the film in more detail.
[0097]
Each will be described below.
First, the in-plane apparent retardation value when viewed from the normal direction of the viewing angle improving film will be described. In a nematic hybrid oriented film, the refractive index in a direction parallel to the director (hereinafter referred to as ne) and the refractive index in a direction perpendicular to the director (hereinafter referred to as no) are different. When the value obtained by subtracting no from no is the apparent birefringence, the apparent retardation value is given by the product of the apparent birefringence and the absolute film thickness. This apparent retardation value can be easily obtained by polarization optical measurement such as ellipsometry. The apparent retardation value in the viewing angle improving film of the present invention is usually in the range of 5 nm to 500 nm, preferably in the range of 10 nm to 300 nm, more preferably in the range of 15 nm to 150 nm with respect to monochromatic light of 550 nm. Is desirable. When the apparent retardation value is less than 5 nm, there is a possibility that a sufficient viewing angle expansion effect cannot be obtained without substantially changing from homeotropic alignment. On the other hand, if it is larger than 500 nm, unnecessary coloration may occur in the liquid crystal display when viewed from an oblique direction.
[0098]
Next, the angle of the director will be described.
The angle range of the director in the film thickness direction of the film for improving the viewing angle with the nematic hybrid orientation fixed is the sharp angle formed by the director of the liquid crystalline polymer at the film interface and the projection component of the director on the film interface. The angle is usually 30 ° or more and 90 ° or less on one of the upper surface or the lower surface of the film, and is usually 0 ° or more and 20 ° or less on the opposite surface of the surface. More preferably, the absolute value of one angle is 40 degrees or more and 90 degrees or less, and the absolute value of the other angle is 0 degrees or more and 10 degrees or less.
[0099]
Next, the average tilt angle will be described.
In the present invention, an average value in the film thickness direction of an angle formed by a director of a liquid crystalline polymer and a projection component of the director onto the substrate plane is defined as an average tilt angle. The average tilt angle can be obtained by applying a crystal rotation method. The average tilt angle of the viewing angle improving film of the present invention is usually in the range of 10 to 60 degrees, preferably in the range of 20 to 50 degrees. When the average tilt angle is smaller than 10 degrees or larger than 60 degrees, although a certain viewing angle expansion effect is recognized, there is a possibility that a satisfactory viewing angle expansion effect cannot be obtained.
[0100]
Next, the arrangement when the viewing angle improving film of the present invention is used for expanding the viewing angle of the TN-LCD will be specifically described. The arrangement position of this film should just be between a polarizing plate and a liquid crystal cell, and can arrange | position one or more viewing angle improvement films. In the present invention, it is practically preferable to perform compensation using one or two viewing angle improving films. Even if three or more films are used, compensation is possible, but this is not preferable because it leads to an increase in cost. A specific arrangement position is exemplified as follows. However, these are only representative arrangement positions, and the present invention is not limited to these.
[0101]
First, the upper and lower surfaces of the viewing angle improving film are defined as follows.
The surface where the angle formed by the director of the liquid crystalline polymer exhibiting optically positive uniaxiality and the film plane forms an angle of 30 ° or more and 90 ° or less on the acute angle side is defined as b-plane. A surface in which the angle forms an angle of 0 ° to 20 ° on the acute angle side is defined as a c-plane.
[0102]
Next, the tilt direction of the viewing angle improving film is defined as follows.
When viewing the c-plane through the liquid crystal layer from the b-plane of the film, the angle between the director and the projection component of the director on the c-plane is an acute angle and the direction parallel to the projection component is the viewing angle improving film. It is defined as the tilt direction.
[0103]
Next, the pretilt direction of the liquid crystal cell is defined as follows.
Usually, at the interface of the liquid crystal cell, the low molecular liquid crystal for driving is not parallel to the interface of the liquid crystal cell but is inclined at a certain angle. This is called the pretilt angle. A direction in which the angle formed by the director of the liquid crystal at the cell interface and the projection component on the director interface is an acute angle, and the direction parallel to the projection component of the director is defined as the pretilt direction of the liquid crystal cell interface.
[0104]
A case where one viewing angle improving film is used for a TN-LCD based on the above definition will be described. The film is disposed between the polarizing plate and the liquid crystal cell, and may be on the upper surface side or the lower surface side of the cell. When the viewing angle improving film is bonded, it is preferable that the tilt direction of the film and the pretilt direction at the liquid crystal cell interface that is not adjacent to each other generally coincide. The angle formed between the tilt direction and the pretilt direction is usually in the range of 0 to 15 degrees, preferably 0 to 10 degrees, more preferably 0 to 5 degrees as an absolute value. If the angle between the two is greater than 15 degrees, there is a possibility that a sufficient viewing angle compensation effect cannot be obtained.
[0105]
Next, the case where two viewing angle improvement films are used for TN-LCD will be described. The two films are arranged on the upper or lower surface of the liquid crystal cell sandwiched between a pair of upper and lower polarizing plates. When arranging, two viewing angle improving films may be on the same side, or one film may be provided on each side. Moreover, the two said films may match | combine with the same parameter, and may differ.
[0106]
In the present invention, when the two viewing angle improving films are arranged separately on the upper and lower sides of the liquid crystal cell, it is preferable to arrange each film in the same arrangement as in the case of using only one sheet. That is, it is preferable that the pretilt direction of the cell liquid crystal at the liquid crystal cell interface that is not adjacent to the liquid crystal cell interface substantially coincides with the title direction of the liquid crystalline composition in each viewing angle improving film. The angle formed between the tilt direction and the pretilt direction is usually in the range of 0 to 15 degrees, preferably 0 to 10 degrees, more preferably 0 to 5 degrees as an absolute value.
[0107]
When two viewing angle improving films are arranged on either the upper surface or the lower surface of the liquid crystal cell, the viewing angle improving film on the side close to the liquid crystal cell is arranged in the same manner as in the case of using one film. In other words, it is preferable that the tilt direction of the viewing angle improving film and the pretilt direction of the nematic liquid crystal at the non-adjacent liquid crystal cell interface are substantially aligned. The angle formed between the tilt direction and the pretilt direction is usually in the range of 0 to 15 degrees as an absolute value, preferably in the range of 0 to 10 degrees, and more preferably in the range of 0 to 5 degrees. The second viewing angle improving film is disposed between the first film and the polarizing plate, and the nematic liquid crystal pretilt direction at the liquid crystal cell interface adjacent to the first film and the second film. It is preferable to arrange the viewing angle improving films so that the tilt directions are substantially the same.
[0108]
Furthermore, since the viewing angle improving film of the present invention has a nematic hybrid orientation, the upper and lower sides of the film are not equivalent. Therefore, when the film is attached to the liquid crystal cell, there are some differences in the viewing angle improvement effect depending on which side is closer to the liquid crystal cell. When the viewing angle improving film of the present invention is actually incorporated into a TN-LCD, a surface having a larger angle formed by the director of the liquid crystalline polymer and the plane of the film (a surface having the angle of 30 degrees or more and 90 degrees or less). It is more desirable to dispose the liquid crystal cell close to the liquid crystal cell and far from the polarizing plate.
[0109]
Finally, the arrangement of the polarizing plates will be described. Usually, in the TN-LCD, the upper and lower polarizing plates may be arranged so that the transmission axes are parallel to each other. When the transmission axes of the upper and lower polarizing plates are orthogonal to each other, the transmission axis of the polarizing plate and the rubbing direction of the liquid crystal cell near the polarizing plate may form an angle of parallel, vertical, or 45 degrees. When the polarizing plate is mounted on the viewing angle improving film of the present invention, the polarizing plate can be arranged in any of the above arrangements, but the viewing angle improving effect can be obtained, but the transmission axes of the upper and lower polarizing plates are arranged perpendicular to each other. Most desirable. The relationship between the transmission axis of the polarizing plate and the rubbing direction applied to the liquid crystal cell on the side close to the polarizing plate can be either parallel or vertical, although there are some differences in the viewing angle improvement effect.
[0110]
The viewing angle improving film of the present invention has a tremendous effect on improving the viewing angle of a TN-LCD using a TFT element or an MIM element, and other modes of LCD, that is, STN (Super Twisted Nematic) -LCD, ECB (Electrically). Controlled Birefringence (LCD), OMI (Optical Mode Interference) -LCD, OCB (Optically Compensated Birefringence) -LCD, HAN (Hybrid Aligned Nematic) LCD, Compensation Is also effective.
[0111]
As described above, the film for an optical element of the present invention sufficiently satisfies reliability such as heat resistance, moisture resistance and light resistance, and has a high film strength. Further, the orientation treatment is possible under a wide range of conditions, and the industrial utility value of the film can be obtained industrially, such as the film having very few unevenness and orientation defects.
[0112]
【Example】
Examples will be described below, but the present invention is not limited thereto. The analytical methods used in the examples are as follows.
(1) Determination of composition of liquid crystalline polymer and determination of structure of compound
Dissolved in deuterated chloroform or deuterated trifluoroacetic acid, 400 MHz¹It was determined using 1 H-NMR (JNM-GX400 manufactured by JEOL).
(2) Logarithmic viscosity measurement
Using an Ubbelohde viscometer, measurement was performed at 30 ° C. in a mixed solvent of phenol / tetrachloroethane (60/40 weight ratio).
(3) Determination of liquid crystal phase series
It was determined by DSC (Perkin Elmer DSC-7) measurement and observation with an optical microscope (BH2 polarizing microscope manufactured by Olympus Optical Co., Ltd.).
(4) Refractive index measurement
The refractive index was measured with an Abbe refractometer (Type-4 manufactured by Atago Co., Ltd.).
(5) Polarization analysis
This was carried out using an ellipsometer DVA-36VWLD manufactured by Mizoji Optical Co., Ltd.
(6) Film thickness measurement
A SURFACE TEXTURE ANALYSIS SY-STEM Dektak 3030ST manufactured by SLOAN was used. Moreover, the method of calculating | requiring a film thickness from the data of interference wave measurement (JASCO Corporation UV / visible / near infrared spectrophotometer V-570) and refractive index data was used together.
[0113]
Reference example 1
40 mmol of terephthalic acid, 40 mmol of 2,6-naphthalenedicarboxylic acid, 85 mmol of catechol diacetate, 80 mmol of acetoxybenzoic acid, 4 hours at 260 ° C. under nitrogen atmosphere, 2 hours at 290 ° C., followed by 290 nitrogen flow at 100 ml per minute Polymerization was carried out at 0 ° C. for 4 hours to obtain a liquid crystalline polyester (Formula 1). This liquid crystalline polyester had a logarithmic viscosity of 0.16, a nematic phase as a liquid crystal phase, an isotropic phase-liquid crystal phase transition temperature of 300 ° C. or higher, and a glass transition point of 120 ° C. A 10 wt% phenol / tetrachloroethane mixed solvent (6/4 weight ratio) solution was prepared using the liquid crystalline polyester. This solution was applied onto a soda glass plate by a bar coating method, dried, heat-treated at 190 ° C. for 30 minutes, and then cooled and fixed at room temperature to obtain a liquid crystal film having a thickness of 1 μm. By observing the film under a polarizing microscope, the portion where the disclination line exists was found while the extinction axes of the adjacent domains were the same, and it was confirmed that the film had tilt orientation.
[0114]
Embedded image

[0115]
Reference example 2
4-octyloxybenzoic acid 10 mmol, terephthalic acid 50 mmol, naphthalenedicarboxylic acid 45 mmol, catechol diacetate 50 mmol, 3-methylcatechol diacetate 50 mmol, 4-acetoxybenzoic acid 50 mmol under nitrogen atmosphere at 270 ° C. for 4 hours, followed by Deacetic acid polymerization was carried out at the same temperature for 2 hours under a nitrogen stream of 30 ml per minute. Next, the obtained reaction product was dissolved in tetrachloroethane, and then purified by reprecipitation with methanol to obtain a liquid crystalline polyester (formula 2). This liquid crystalline polyester had a logarithmic viscosity of 0.10, a nematic phase as a liquid crystal phase, an isotropic phase-liquid crystal phase transition temperature of 240 ° C., and a glass transition point of 75 ° C.
[0116]
A 10 wt% phenol / tetrachloroethane mixed solvent (6/4 weight ratio) solution was prepared using the liquid crystalline polyester. This solution was applied onto a soda glass plate by spin coating, dried, heat-treated at 220 ° C. for 30 minutes, cooled and fixed at room temperature, and a uniformly oriented film having a thickness of 10 μm was obtained. Conoscopic observation of the film confirmed that the film was a homeotropic alignment film.
[0117]
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[0118]
Reference example 3
10 mmol of tert-butyl hydroquinone diacetate and 20 mmol of 6-pentyloxy-2-naphthoic acid were reacted at 250 ° C. for 4 hours under a nitrogen atmosphere for 2 hours at 270 ° C., followed by 2 hours at 270 ° C. under a nitrogen stream of 30 ml per minute. . Subsequently, the compound was recrystallized from a mixed solvent of methanol / ethyl acetate = 1/1 to obtain a compound of formula (3).
[0119]
Embedded image

[0120]
Example 1
A liquid crystalline composition was prepared by blending 75 parts of the liquid crystalline polyester (Formula 1) obtained in Reference Example, 20 parts of the liquid crystalline polyester (Formula 2), and 5 parts of the compound (Formula 3). Next, an 8 wt% tetrachloroethane solution of the composition was prepared. The solution was applied onto a glass substrate having a rubbing polyimide film by spin coating, dried, and heat-treated at 220 ° C. for 20 minutes. After the heat treatment, the film 1 was air-cooled to obtain a film 1. The obtained film 1 on the glass substrate was transparent and had no alignment defect, and the film thickness was 1.55 μm.
[0121]
Using the optical measurement system shown in FIGS. 1 and 2, the film 1 was tilted in the rubbing direction of the substrate, and the retardation value was measured. As a result, as shown in FIG. 3, the result was asymmetrical and there was no angle at which the retardation value was zero. From this result, it was found that the director of the liquid crystalline polyester is tilted with respect to the substrate and is not in a uniform tilt orientation (an orientation state in which the angle between the director and the substrate surface is constant in the film thickness direction).
[0122]
Next, the film 1 on the substrate was cut into five pieces, each immersed in a methanol solution containing 3 wt% of chloroform for a certain time, and eluted from the upper surface of the liquid crystal layer. When the immersion time was 15 seconds, 30 seconds, 1 minute, 2 minutes, and 5 minutes, the film thicknesses of the liquid crystal layer that remained without being eluted were 1.35 μm, 1.10 μm, 0.88 μm, and. 56 μm and 0.37 μm. The retardation value (frontal retardation value) in the case of θ = 0 degrees was measured using the optical system of FIGS. 1 and 2, and the relationship between the film thickness and the retardation value in FIG. 4 was obtained. As can be seen from FIG. 4, the film thickness and the retardation value are not in a linear relationship, and from this, it was found that the tilt alignment is not uniform. The dotted line in the figure is a straight line normally observed in a film with uniform tilt orientation.
[0123]
Next, the liquid crystalline composition is aligned and fixed on a high refractive index glass substrate (refractive index is 1.84) having a rubbing polyimide film by using the same method as above to produce a film 1 ′. Refractive index measurement was performed using the film. When the glass substrate is placed in contact with the prism surface of the refractometer and the substrate interface side of the film 1 'is positioned below the air interface side, the refractive index in the film surface has anisotropy and is in the rubbing direction. The refractive index in the vertical plane was 1.55, the refractive index in the parallel plane was 1.71, and the refractive index in the film thickness direction was constant at 1.55 regardless of the direction of the film 2. From this, it was found that on the glass substrate side, the rod-like liquid crystal molecules constituting the liquid crystalline polyester were planarly aligned parallel to the substrate. Next, when the air interface side of the film 1 'was in contact with the prism surface of the refractometer, the in-plane refractive index had no anisotropy and the refractive index was constant at 1.55. Further, the refractive index in the film thickness direction is constant at 1.71 regardless of the direction of the film 1 ′. Therefore, on the air interface side, the rod-like liquid crystal molecules constituting the liquid crystalline polyester are aligned perpendicular to the substrate plane. Turned out to be.
[0124]
From the above, the film obtained in this example forms a nematic hybrid orientation, and is oriented as shown in FIG. 5 by the regulating force at the substrate interface and the regulating force at the air interface by rubbing. There was found.
[0125]
Next, the following operation was performed in order to obtain the director angle at the substrate interface more accurately.
On the film 1 ′ formed on the high refractive glass substrate having the rubbing polyimide film, another glass substrate having the rubbing polyimide film was covered and adhered. That is, the film 1 'was sandwiched between two rubbing polyimide films. At this time, the rubbing directions of the upper and lower rubbing films were arranged so as to be 180 degrees to each other. In this state, heat treatment was performed at 190 ° C. for 30 minutes. The sample film thus obtained was subjected to refractive index measurement and polarization analysis. As a result of the refractive index measurement, the same value was obtained with respect to the upper and lower sides of the sample film, and the refractive index in the film plane was 1.55 in the plane perpendicular to the rubbing direction, 1.71 in the plane parallel to the film, It was 1.55 in the thickness direction. From this, it has been found that the director is substantially parallel to the substrate plane both above and below the sample film near the interface of the substrate. Furthermore, as a result of ellipsometry, the refractive index structure is almost positive uniaxial. As a result of detailed analysis based on the crystal rotation method, there is a slight inclination of the director near the substrate interface, and the substrate plane and director The angle formed by was about 3 degrees. Further, the direction in which the director tilted coincided with the rubbing direction (the film tilt direction coincides with the rubbing direction).
[0126]
From the above, assuming that the orientation of the director at the substrate interface is substantially determined by the interaction between the liquid crystalline polymer and the alignment substrate interface, the film 1 and the film 1 ′ formed on the single alignment substrate described above. The director orientation at the substrate interface in this nematic hybrid orientation is estimated to be 3 degrees.
[0127]
Example 2
An 8 wt% tetrachloroethane solution was prepared using the same liquid crystal composition as in Example 1. The solution was applied on a glass substrate having a rubbing polyimide film by spin coating and dried. Subsequently, after heat-processing for 10 minutes at 210 degreeC, it cooled and the film 2 was obtained. The film 2 on the substrate was transparent and uniform with no alignment defects. The film thickness was 0.42 μm, and the average tilt angle in the film thickness direction was 36 degrees.
[0128]
Two films 2 were used, and each optical element was arranged with the axial arrangement shown in FIG. At this time, one film 2 was placed above and below the liquid crystal cell so that the air interface side of the film 2 was close to the liquid crystal cell. The liquid crystal cell used uses ZLI-4792 as the liquid crystal material, and the cell parameters are a cell gap of 4.8 μm, a twist angle of 90 degrees (left twist), and a pretilt angle of 4 degrees. A voltage was applied to the liquid crystal cell with a rectangular wave of 300 Hz. Measure the contrast ratio from all directions using the FFP optical system DVS-3000 from Hamamatsu Photonics Co., Ltd. with the ratio of the transmittance of white display 0V and black display 6V (white display) / (black display) as the contrast ratio. Draw an isocontrast curve. The result is shown in FIG.
In the arrangement of FIG. 6, the gradation characteristics in the horizontal direction (0 ° -180 ° direction) by applying a voltage that divides the transmittance difference between the white display and the black display into eight equal parts is applied to the liquid crystal cell. Measurement was performed using a color luminance meter BM-5. The results are shown in FIG.
[0129]
Comparative Example 1
Using the same TN type liquid crystal cell as in Example 2 except that the film 2 is not mounted, the contrast ratio is measured in all directions under the same conditions, and the gradation characteristics are measured in the horizontal direction (0 ° -180 ° direction). Went. The results are shown in FIGS.
[0130]
Reference example 4
22 mmol of 4- (2-ethylhexyloxy) phenol was dissolved in 500 ml of pyridine, and a solution prepared by dissolving 10 mmol of terephthalic acid dichloride in 200 ml of methylene chloride was added dropwise over 30 minutes while stirring with a mechanical stirrer. After reacting at 0 ° C. for 2 hours and at room temperature for 5 hours, pyridine was distilled off under reduced pressure. To the residue was added 500 ml of 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The extract was washed again with 1N hydrochloric acid, and then washed successively with water, aqueous sodium bicarbonate, and saturated brine. Then, the extract was dried over magnesium sulfate, and then the solvent was distilled off. Subsequently, the residue was recrystallized from a mixed solvent of methanol / ethyl acetate to obtain a compound of formula 4.
[0131]
Embedded image

[0132]
Example 3
A liquid crystalline composition was prepared by blending 70 parts of the liquid crystalline polyester (formula 1), 27 parts of the liquid crystalline polyester (formula 2), and 3 parts of the compound (formula 4) obtained in the reference example. Next, a 10 wt% N-methylpyrrolidone solution of the composition was prepared. Furthermore, in order to lower the surface tension of the solution, 0.005% of KH-40 (manufactured by Asahi Glass Co., Ltd.) was added as a surfactant with respect to the total weight of the solution.
The film 3 was obtained by coating, drying and heat treatment under the same conditions as in Example 2. The film 3 had a thickness of 0.50 μm, and the average tilt angle in the thickness direction was 30 degrees. The contrast ratio from all directions was measured by the same method as in Example 2 using the film. The result is shown in FIG.
[0133]
Reference Example 5
Deacetic acid reaction was performed using 20 mmol of 4-benzyloxybenzoic acid and 10 mmol of catechol diacetate under a nitrogen atmosphere at 270 ° C. for 4 hours, and then at the same temperature for 2 hours under a nitrogen stream of 30 ml per minute. The obtained reaction product was dissolved in tetrachloroethane and then reprecipitated with methanol to obtain the compound of formula 5.
[0134]
Embedded image

[0135]
Then, the compound was dissolved in 500 ml of ethyl acetate, and subjected to hydrogenolysis reaction under a hydrogen atmosphere of 2 atm at room temperature for 24 hours with 1 g of 5% Pd / C catalyst to remove the benzyl group. Subsequently, the reactive product was dissolved in a mixture of 500 ml of methylene chloride to which 1 g of dimethylaminopyridine was added and 100 ml of pyridine, and a solution of 20 mmol of 4-octyloxybenzoic acid chloride in 200 ml of methylene chloride was added at 0 ° C. over 30 minutes. It was dripped. After reacting at 0 ° C. for 2 hours and at room temperature for 5 hours, pyridine was distilled off under reduced pressure. To the residue was added 500 ml of 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The extract was washed again with 1N hydrochloric acid, and then washed successively with water, aqueous sodium bicarbonate, and saturated brine. The extract was then dried over magnesium sulfate, the solvent was distilled off, the residue was subsequently dissolved in chloroform, and the solution was reprecipitated in methanol to obtain the compound of formula 6.
[0136]
Embedded image

[0137]
Reference Example 6
20 mmol of 2-benzyloxyphenol was dissolved in 500 ml of pyridine, and a solution of 10 mmol of 4,4′-oxybis (benzoic acid dichloride) dissolved in 200 ml of methylene chloride was added dropwise over 30 minutes at 0 ° C. while stirring with a mechanical stirrer. . After reacting at 0 ° C. for 2 hours and at room temperature for 5 hours, pyridine was distilled off under reduced pressure. To the residue was added 500 ml of 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The extract was washed again with 1N hydrochloric acid, and then washed sequentially with water, aqueous sodium bicarbonate, and saturated brine. The extract was then dried over magnesium sulfate and the solvent was distilled off. The obtained residue was recrystallized using a mixed solvent of methanol / ethyl acetate to obtain a compound of formula 7.
[0138]
Embedded image

[0139]
Then, the compound was dissolved in 500 ml of ethyl acetate, and subjected to hydrogenolysis reaction under a hydrogen atmosphere of 2 atm at room temperature for 24 hours with 1 g of 5% Pd / C catalyst to remove the benzyl group. Subsequently, the reactive product was dissolved in a mixture of 500 ml of methylene chloride added with 1 g of dimethylaminopyridine and 100 ml of pyridine, and a solution of 20 mmol of 4′-butoxystilbene-4-carboxylic acid chloride in 200 ml of methylene chloride at 0 ° C. It was added dropwise over 30 minutes. After reacting at 0 ° C. for 2 hours and at room temperature for 5 hours, pyridine was distilled off under reduced pressure. To the residue was added 500 ml of 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The extract was washed again with 1N hydrochloric acid, and then washed successively with water, aqueous sodium bicarbonate, and saturated brine. The extract was then dried over magnesium sulfate, the solvent was distilled off, the residue was subsequently dissolved in N-methylpyrrolidone, and the solution was reprecipitated in methanol to obtain the compound of formula 8.
[0140]
Embedded image

[0141]
Reference Examples 7-18
10 mmol of the compound of X in Table 1 and 20 mmol of the compound of Y in Table 1 were mixed and reacted at 250 ° C. for 4 hours in a nitrogen atmosphere for 2 hours at 270 ° C., followed by 2 hours at 270 ° C. in a nitrogen stream of 30 ml per minute I let you. Compounds (11), (13), (15), (16), (17), and (20) were further purified by recrystallization from a mixed solvent of methanol / ethyl acetate = 1/1. On the other hand, for the compounds (9), (10), (12), (14), (18) and (19), the crude product is dissolved in chloroform and then added dropwise to methanol to reprecipitate the product. Purified.
[0142]
[Table 1]

[0143]
Embedded image

[0144]
Embedded image

[0145]
Embedded image

[0146]
Reference Examples 19-25
20 mmol of a compound represented by X in Table 2 was dissolved in 500 ml of pyridine, and a solution prepared by dissolving 10 mmol of a compound represented by Y in Table 2 in 200 ml of methylene chloride was added dropwise over 30 minutes while stirring with a mechanical stirrer. . After reacting at 0 ° C. for 2 hours and at room temperature for 5 hours, pyridine was distilled off under reduced pressure. To the residue was added 500 ml of 1N hydrochloric acid, and the mixture was extracted with ethyl acetate. The extract was washed again with 1N hydrochloric acid, and then washed sequentially with water, aqueous sodium bicarbonate, and saturated brine. The extract was then dried over magnesium sulfate and the solvent was distilled off.
[0147]
Thereafter, the compounds (21), (23), (25), (26), and (27) were purified by recrystallization from a mixed solvent of methanol / ethyl acetate = 1/1. On the other hand, the compounds (22) and (24) were purified by dissolving the crude product in chloroform and then dropping it into methanol to reprecipitate the product.
[0148]
[Table 2]

[0149]
Embedded image

[0150]
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[0151]
Examples 4-34
A film was prepared in the same manner as in Example 3, and the results of evaluating the film are shown in Table 3.
[0152]
[Table 3]

[Brief description of the drawings]
FIG. 1 is a layout view of an optical measurement system used for measuring a tilt angle of a film for optical elements of the present invention.
FIG. 2 shows the relationship between the axial orientation of a sample of an optical measurement system and a polarizing plate used for measuring the tilt angle of the film for optical elements of the present invention.
3 shows the relationship between the apparent retardation value measured by tilting along the rubbing direction of the substrate and the tilt angle of the sample (film 1) in Example 1. FIG.
4 shows the measurement results of the film thickness after immersion of film 1 and the apparent retardation value in front of the sample in Example 1. FIG.
5 is a conceptual diagram of an orientation structure of a film 1 obtained in Example 1. FIG.
6 shows an axial arrangement of optical elements in Example 2. FIG.
7 shows an isocontrast curve of Example 2. FIG.
FIG. 8 shows a measurement result of gradation characteristics in the horizontal direction in Example 2;
9 shows an isocontrast curve of Comparative Example 1. FIG.
10 shows gradation characteristics in the horizontal direction of Comparative Example 1. FIG.
11 shows an isocontrast curve of Example 3. FIG.

Claims (2)

The liquid crystalline polyester (a) exhibiting optically positive uniaxiality and a plurality of alicyclic rings and / or aromatic rings are bonded via a connecting chain having 0 to 4 main chain atoms bonded to different ring carbon atoms. A polycyclic compound (b) having a molecular weight of 1000 or less in which a hydrocarbon group having 1 to 20 carbon atoms is bonded to each terminal ring via a connecting chain having 0 to 4 main chain atoms. A film for optical elements, characterized in that it is formed from at least a liquid crystalline composition contained therein, and an alignment form formed by the liquid crystalline composition in a liquid crystal state is fixed.   2. The film for an optical element according to claim 1, wherein the alignment form is nematic hybrid alignment.

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